Window cleaning robot

ABSTRACT

A window-cleaning robot that includes: a powered agitator that, when active, mechanically removes debris from a window surface; a cleaning pad, which is wetted with a cleaning fluid and contacts the window surface so as to remove debris therefrom with the aid of the cleaning fluid; and a movement system, for example including a number of wheels, which moves the robot over the window surface and has a defined forwards direction; the agitator is located forwards of the cleaning pad and the agitator and the cleaning pad are arranged such that, as the robot moves over the window surface in the forwards direction, the agitator addresses a width in a width direction, which is perpendicular to the forwards direction and parallel to the window surface, that is greater than the width addressed by the cleaning pad.

TECHNICAL FIELD

The present invention relates to robotics and, in particular, to roboticwindow cleaners.

BACKGROUND

The use of automated devices is widespread nowadays, and finds countlessapplications. For instance, robots perform very precise and delicatetasks in the construction of electronic devices, or in medicine andaviation. Robots are also used in applications which require motion,notably, for automatic warehouses, where goods are retrieved and storedby means of computer-actuated robots. Other applications include, e.g.,fetching raw materials in the course of industrial manufacturing, andremoving and packaging finished pieces.

Attempts have also been made to exploit robots for tasks around the homeor garden, such as lawn mowing, snow-blowing, leaf-clearing, floorcleaning, pool cleaning and vacuum cleaning.

By their very nature, autonomous machines such as robots represent asignificant labour-saving for consumers. Repetitive and time-consumingtasks may now be carried out without significant supervision orinstruction by the user of such autonomous machines.

Window cleaning is an example of such a repetitive and time-consumingtask. A robotic window cleaner may be valuable not only in reducingmanual labour, but also in allowing the cleaning of window surfaces thatare usually hard to access, such as the external surfaces of windowsand/or windows that are high above the ground.

A few window cleaning robots are currently available to the consumer,such as the WinBot and Hobot. However, in many respects, robotic windowcleaners have not yet been perfected.

SUMMARY

In a first aspect, the following disclosure describes a window-cleaningrobot comprising: a movement system configured for moving the robot overa window surface and operable with a predefined forwards direction ofmovement; at least one agitator configured for removing debris from awindow surface; at least one cleaning pad for removing debris from thewindow surface, the at least one cleaning pad arranged on the robot tofollow the at least one agitator when the movement system moves therobot in the predefined forwards direction of movement; and wherein saidat least one agitator and said at least one cleaning pad are arrangedsuch that, as said movement system moves the robot over the windowsurface in said forwards direction, the at least one agitator addressesa first width in a width direction, which is perpendicular to saidforwards direction and parallel to the window surface, and at least onecleaning pad addresses a second width in said width direction, saidfirst width being substantially equal to or greater than said secondwidth.

In some examples, each of said at least one agitator is elongate in saidwidth direction. Optionally, each of the at least one cleaning pad iselongate in said width direction.

The robot may further comprise one or more reservoirs fillable withcleaning fluid, the one or more reservoirs being fluidically connectedso as to supply said cleaning fluid to said at least one cleaning pad.

Optionally, each of said at least one cleaning pad comprises a cloththat is wettable by said cleaning fluid, preferably wherein said clothis a microfiber cloth.

In some examples, the robot may further comprise one or more polishingpads configured to contact the window surface and, thereby, to polish itwhen the robot is moved over the window surface using said movementsystem. Optionally, each polishing pad polishes the window surface suchthat any layer of cleaning fluid present on the window surface is leftas a thinner layer and/or is dispersed over a greater area after thepolishing pad passes over it. Optionally, each polishing pad polishesthe window surface such that variation in the depth of any layer ofcleaning fluid present on the window surface is reduced after thepolishing pad passes over it. Optionally, said at least one polishingpad is arranged such that, as the robot moves over the window surface insaid forwards direction, the at least one polishing pad addresses athird width in said width direction, said third width beingsubstantially equal to said second width. Optionally, each polishing padis elongate in said width direction. Optionally, said at least onepolishing pad comprises a rearwards one or more polishing pads, said theat least one cleaning pad being located beyond said rearwards one ormore polishing pads in said forwards direction. Optionally, said one ormore polishing pads additionally comprise a forwards one or morepolishing pads, which are located beyond said cleaning pads in saidforwards direction. Optionally, said forwards one or more polishing padsare substantially the same as said rearwards one or more polishing pads.Optionally, each polishing pad comprises a cloth that is wettable bysaid cleaning fluid. Optionally, each cleaning pad cloth and eachpolishing pad cloth is formed of fibres, the fibres of said cleaning padcloths being substantially finer than those of the polishing pad cloths.

In some examples, the robot may further comprise an attachment system,for attaching the robot to the surface of a window, the attachmentsystem comprising: at least one first sealing member, each of which isattached to the robot and configured to contact the surface of a windowso as to seal a respective space between the robot and the windowsurface; one or more vacuum pumps, operable to reduce the air pressurewithin the spaces sealed by said one or more first sealing members;wherein, with respect to said width direction said at least one firstsealing member lies substantially wholly within said first width.

In some examples, said at least one agitator is located beyond said oneor more first sealing members in said forwards direction.

In some examples, said at least one first sealing members is locatedbeyond said at least one cleaning pad in said forwards direction.

The robot may comprise one or more processors. Optionally, each firstsealing member is an active-mode sealing member, the one or moreprocessors being programmed to operate in one or more active modes,where the robot moves over the surface of window, using said movementsystem, and the vacuum pump(s) are caused to reduce the air pressurewithin the spaces sealed by the active-mode sealing members to asufficient extent to attach the robot to the window surface, whilepermitting movement of the robot over the window surface.

In some examples, said agitator may comprise a brush. In addition, orinstead, said at least one agitator is configured such that debris issubstantially swept clear of said at least one cleaning pad. Optionally,each of the at least one agitator is rotatable. Optionally, the axis ofrotation of each of the at least one agitator is parallel to the windowsurface. Optionally, the axis of rotation of each of the at least oneagitator is parallel to the width direction. Optionally, the directionof rotation is such that the portions of each agitator contacting thewindow surface are moving generally in said forwards direction.Optionally, the agitator is substantially less wettable by said cleaningfluid than said cleaning pad.

In a further aspect, the following disclosure describes awindow-cleaning robot comprising: one or more processors; an attachmentsystem, for attaching the robot to the surface of a window, theattachment system comprising: an active-mode sealing member, attached tothe robot and configured to contact the surface of a window so as toseal a respective space between the robot and the window surface; one ormore paused-mode sealing members, each of which is attached to the robotand configured to contact the window surface so as to seal a respectivespace between the robot and the window surface; and one or more vacuumpumps, which are operable to reduce the air pressure within the spacessealed by the active-mode sealing member and the one or more paused-modesealing members; and a movement system, configured to move the robotover the window surface; the one or more processors being programmed tooperate in a paused mode, where the one or more processors cause therobot to remain stationary on the surface of the window, and one or moreactive modes, where one or more processors cause the robot to move overthe surface of window, using said movement system; the one or moreprocessors being additionally programmed such that, in each of said oneor more active modes, the vacuum pump(s) are caused to reduce the airpressure within the space sealed by the active-mode sealing member to asufficient extent to attach the robot to the window surface, whilepermitting movement of the robot over the window surface; the robotbeing additionally programmed such that, in said paused mode, they causethe one or more vacuum pumps to reduce the air pressure within thespaces sealed by the paused-mode sealing member(s) to a sufficientextent to attach the robot to the window surface.

In some examples, said one or more vacuum pumps consume significantlyless power in said paused mode than in said active modes.

In some examples, the robot may further comprise one or more airpressure sensors, each air pressure sensor being arranged to sense theair pressure within the space between a corresponding one of the one ormore paused-mode sealing members and the window surface, wherein the oneor more processors are programmed such that the one or more vacuum pumpsare operated in dependence upon the air pressure within the respectivespaces between the one or more paused-mode sealing members and thewindow surface, as measured by the one or more air pressure sensors.Optionally, the one or more processors are further programmed such that,during said paused mode, they cause the one or more vacuum pumps toreduce the air pressure within the respective spaces sealed between thepaused-mode sealing member(s) and the window surface, as measured by theair pressure sensor(s), to below a first threshold value and,thereafter, it deactivates the one or more vacuum pumps until the airpressure within the space sealed by the one or more paused-mode sealingmembers, as measured by the one or more air pressure sensor, rises abovea second threshold value.

In some examples, each of the one or more paused-mode sealing members ismoveable between a first position, where it is spaced apart from thewindow surface, and a second position, where it contacts the windowsurface so as to seal said space between the robot and the windowsurface. Optionally, each of the one or more paused-mode sealing membersare biased towards said first position. Optionally, movement betweensaid first position and said position includes deformation of the one ormore paused-mode sealing member; the first position may, for example,correspond to a substantially undeformed state of each paused-modesealing member.

In some examples, the one or more processors may be further programmedsuch that, during said paused mode, they causes each of the one or morepaused-mode sealing members to move to said second position and, duringeach of said active modes, it causes each of the one or more paused-modesealing members to return to said first position.

In some examples, the active-mode sealing member and said one or morepaused-mode sealing members are arranged such that said active-modesealing member remains in contact with the window surface whether therobot is operating in said paused mode or in any of the active modes.

In some examples, the robot may further comprise a respective internalspace for each of said one or more paused-mode sealing members, said oneor more vacuum pumps being configured to reduce the air pressure withinsaid internal spaces so as to move each of said one or more paused-modesealing members to said second position. Optionally, the robot mayfurther comprise, for each of said one or more paused-mode sealingmembers, a respective valve and a respective conduit, each conduitconnecting the internal space for the corresponding one of thepaused-mode sealing members with the space sealed by that paused-modesealing member via the corresponding one of said valves; wherein eachvalve permits the passage of air through the corresponding one of theconduits when the pressure within the corresponding internal space isbelow a third threshold value and inhibits the passage of air throughthe corresponding one of the conduits when the pressure within thecorresponding internal space is above said third threshold value.

In some examples, said at least one vacuum pump includes first andsecond sets of vacuum pumps, said first set being dedicated to saidactive-mode sealing member and said second set being dedicated to saidone or more paused-mode sealing members. Optionally, each vacuum pumpwithin said first set comprises one or more impellers. Optionally, eachvacuum pump within said second set is a diaphragm vacuum pump. In someexamples, the first set may consist of a single vacuum pump; in otherexamples, a dedicated vacuum pump is provided for each paused-modesealing member. In some examples, the second set consists of a singlevacuum pump.

In some examples, said one or more paused-mode sealing members arelocated within said active-mode sealing member.

In a still further aspect, the following disclosure describes awindow-cleaning robot comprising: a main body; a movement system,mounted on said main body and configured to move the robot over thesurface of a window; a cleaning pad member, which comprises one or morecleaning pads, each cleaning pad being configured to be wetted with acleaning fluid and to contact the window surface so as to remove debristherefrom with the aid of the cleaning solution; wherein the cleaningpad member is moveably mounted on the main body such that when thecleaning pad member contacts a frame for the window, the frame pushesthe cleaning pad member, causing the cleaning pad member to move withrespect to the body thereby allowing at least a portion of the main bodyto approach closer to said window frame.

In some examples, the cleaning pad member is moveably mounted on themain body such that when the cleaning pad member contacts a frame forthe window, the cleaning pad member moves with respect to the bodythereby allowing at least a portion of the main body to approach closerto said window frame in at least one of the following situations: whenturning on the spot adjacent to the window frame; when moving along acurved path that passes through a point adjacent the frame; and whenmoving along a path substantially parallel to the window frame.

Optionally, the cleaning pad member is moveably mounted at a locationadjacent a first end of the main body. Optionally, the profile of themain body, when viewed from the side that contacts the window surface,is narrower at said first end. Optionally, the movement system has aforwards direction and an opposing rearwards direction, and wherein saidfirst end is the rearwards end of the main body. Optionally, the portionof the main body on which the cleaning pad member is mounted, whenviewed from the side that contacts the window surface, has a curvedprofile.

In some examples, the cleaning pad member is moveably mounted on themain body such that the cleaning pad member is mechanically biasedtowards a central position. Optionally, the movement system has aforwards direction, and wherein, in said central position, the cleaningpad member is aligned, along said forwards direction, with the mainbody.

In some examples, the cleaning pad member, and optionally the cleaningpad, is elongate in a first direction and is moveably mounted on themain body such that movement is restricted to said first direction.Optionally, the movement system has a forwards direction, which isperpendicular to said first direction.

In some examples, the movement system has a forwards direction andwherein the cleaning pad member defines the width of the robot in awidth direction, which is perpendicular to the forwards direction andparallel to the plane of the window surface.

In some examples, the robot further comprises a mechanical arm, thecleaning pad member being moveably mounted on the main body using saidarm, preferably wherein the mechanical arm pivots on the main body.

In yet a further aspect, the following disclosure describes a windowcleaning robot comprising: one or more processors; at least oneorientation sensor, one or more processors being programmed to determinea robot orientation using said at least one orientation sensor; whereinone or more processors are programmed to operate in a plurality ofoperation modes; and wherein the one or more processors are programmedso as to allow the user to select one of said operation modes, theuser-selected operation mode being determined by the one or moreprocessors based at least in part on the robot orientation.

The orientation sensor(s) may, for example, comprise a gyroscope and/oran accelerometer.

In some examples, the robot further comprises an operation mode control,actuation of which determines, in part, said user-selected operationmode. Optionally, said operation mode control has an unactuated and anactuated state and, for example, is biased towards the unactuated state.

In some examples, said plurality of operation modes comprises a pausedmode, where the robot remains stationary on the surface of the window,and a plurality of active modes, where the robot moves over the surfaceof window; and

In some examples, each actuation of said operation mode control switchesthe robot between said paused mode and a user-selected one of saidactive modes, the user-selected active mode being determined based onthe robot direction. Optionally, said at least one active mode includesa spot cleaning mode where the robot window cleaner is configured toclean a predetermined area local to the robot, optionally wherein saidspot cleaning mode is selected when the robot direction is generallyhorizontal. Optionally, said at least one active mode includes a “fullcleaning” mode where the robot window cleaner is configured to cleansubstantially the entire surface of the window, optionally wherein saidfull cleaning mode is selected when the robot direction is generallyvertical. Optionally, said at least one active mode includes one of: a“scan down” mode, where the robot is configured to clean the surface ofthe window below the robot's current height; and a “scan up” mode wherethe robot is configured to clean the surface of the window above therobot's current height; optionally wherein the respective one of said“scan down” and “scan up” modes is selected when the robot direction isgenerally horizontal. Optionally, said at least one active modeincludes: a “scan down” mode, where the robot is configured to clean thesurface of the window below the robot's current height; and a “scan up”mode where the robot is configured to clean the surface of the windowabove the robot's current height; optionally wherein said “scan down”mode is selected when the robot direction is generally horizontal andtowards a predetermined one of the left-hand side and the right-handside of the window and said “scan up” mode is selected when the robotdirection is generally horizontal and towards the other of the left-handside and the right-hand side of the window. Optionally, said at leastone active mode includes a return to docking station mode where therobot window cleaner is configured to move to a docking station.

In some examples, said at least one active mode includes one or more“scanning” modes, wherein, in each “scanning” mode, the one or moreprocessors are programmed to cause the robot to clean a central portionof the window surface, which is substantially the entire window surface,with the exception of a perimeter portion of the window surface adjacentthe edge of the window. The perimeter portion of the window surface may,for example, extend a distance less than the width of the robot from theedge of the window.

Optionally, in each of said “scanning” modes, the robot is programmed tomove along a path defined in the robot's programming such that itcomprises a plurality of parallel first segments, each of which extendsparallel to a scanning direction corresponding to that “scanning” mode,thereby cleaning said central portion of the window surface. The firstsegments may, for example, make up the majority of the length of thepath. Each of said first segments may, for instance, extend from aposition adjacent one edge of the window to a position adjacent theopposite edge of the window surface.

In some examples, the one or more processors are programmed to determinewhich of said scanning directions is closest to said robot direction andto select the “scanning” mode corresponding to that closest scanningdirection. The “scanning” modes may, for example, include a “verticalscanning” mode, having a vertical scanning direction, and a “horizontalscanning” mode, having a horizontal scanning direction. In some cases,the “scanning” modes consist of said “vertical scanning” and “horizontalscanning” modes.

In some examples, in each of said “scanning” modes, the path is definedin the programming of the one or more processors such that the pathfurther comprises a series of second segments, each of which linkstogether two of said first segments. Optionally, in at least one of said“scanning” modes, the path is defined in the programming of the one ormore processors such that said second segments are turning segments,where the robot carries out a generally smooth turn. As a furtheroption, in at least one of said “scanning” modes, the path is defined inthe programming of the one or more processors such that said secondsegments are perpendicular to said first segments.

In some examples, the robot may further comprise a movement systemhaving a defined forwards direction, the robot direction beingdetermined by the one or more processors in such a way that it isparallel to said forwards direction.

In a still further aspect, the following disclosure describes a windowcleaning robot comprising: one or more processors; at least oneorientation sensor, the robot being configured to determine itsorientation using said orientation sensor(s); and/or at least oneproximity sensor, the robot being configured to determine whether it isin close proximity to the surface of a window using said at least oneproximity sensor; the robot additionally comprising an attachment systemconfigured to provide an attachment force by which the robot is attachedto the window surface; wherein the one or more processors are programmedso as to cause the attachment force to be varied based on the robotorientation, as determined using said orientation sensor(s) and/or theproximity of the robot to the surface of the window, as determined bysaid at least one proximity sensor.

The orientation sensor(s) may, for example, comprise a gyroscope and/oran accelerometer.

In examples where the robot comprises at least one proximity sensor, theone or more processors may be programmed to increase the attachmentforce to above a first threshold value when they determine that therobot is in close proximity to the surface of the window using the atleast one proximity sensor.

In examples where the robot comprises at least one orientation sensor,the one or more processors may be programmed such that, when theydetermine that the robot is in close proximity to the surface of thewindow using the at least one proximity sensor, they cause theattachment force to be increased to a level that is greater than saidfirst threshold value by an amount determined in accordance with therobot orientation with respect to the horizontal, as determined usingsaid orientation sensor(s). Optionally, the amount determined inaccordance with the robot direction is substantially equal to zero wherethe robot orientation is within a predetermined angular range of thehorizontal.

Optionally, the one or more processors may be programmed such that, whenthey determines that the robot is not in close proximity to the surfaceof the window using the at least one proximity sensor, the attachmentforce is set to a level that is equal to or less than a second thresholdvalue.

In some examples, the second threshold value may be substantially equalto zero. Optionally, the first threshold value is equal to said secondthreshold value. Optionally, the first threshold value is substantiallyequal to zero.

In some examples, the variable attachment force may be provided bysuction. In such examples, the robot may further comprise an airpressure sensor configured to measure an air pressure in the attachmentsystem. Further, the one or more processors may be programmed to varythe attachment force based on the air pressure measured by said airpressure sensor. In addition, or instead, the one or more processors maybe programmed so as to increase the attachment force to above athreshold value when the air pressure measured by said air pressuresensor drops below a predetermined pressure. The predetermined pressuremay, for example, be a predetermined amount below local atmosphericpressure. The one or more processors may optionally be programmed todetermine local atmospheric pressure by use of said air pressure sensorwhen the robot is not attached to the window surface. The attachmentsystem may optionally further comprise an impeller, wherein theattachment force is varied by varying the speed at which the impellerturns.

In some examples, the one or more processors may be programmed so as tovary said attachment force so as to keep the robot window cleanerattached to the window surface.

In some examples, the one or more processors may be programmed to causethe attachment system to increase the level of the variable attachmentforce when unwanted motion of the robot window cleaner is detected. Therobot may suitably further comprise one or more navigation sensors, theone or more processors being programmed to determine the motion of therobot relative to the window using said one or more navigation sensors;wherein the robot is programmed to detect unwanted motion using said oneor more navigation sensors. Optionally, the robot further comprises anundriven wheel arranged to roll over the window surface as the robotmoves over the window surface; and wherein at least one of said one ormore said navigation sensors is a sensor configured to detect therotation of said undriven wheel. Suitably, at least one of the one ormore navigation sensors is a sensor operable to sense the relativemotion of the robot, for example: an odometer; an accelerometer; agyroscope; and/or a magnetometer. Optionally, at least one of said oneor more navigation sensors is a sensor configured to sense the distanceto a frame of the window extending perpendicular to the surface of thewindow.

In still another aspect, the following disclosure describes a windowcleaning robot comprising: one or more processors; a movement system,configured to move the robot over the surface of a window and, thereby,to enable the robot to clean the window surface; at least oneorientation sensor, the one or more processors being programmed todetermine the orientation of the robot using said at least oneorientation sensor; at least one distance sensor configured to detectthe distance between the robot and the frame of the window; wherein theone or more processors are programmed to cause the robot to move, usingsaid movement system, over the window surface, navigating based onmeasurements provided by said orientation sensor(s) and said distancesensor(s).

In some examples, the one or more processors are further programmed touse said measurements provided by the orientation sensor(s) and thedistance sensor(s) to move along a path over the window surface.

The orientation sensor(s) may, for example, comprise a gyroscope and/oran accelerometer.

Suitably, the path is such that the robot does not pass over the sameportion of the window surface twice while moving along said path. Inaddition, or instead, the path may not cross itself.

In some examples, the movement system has a forwards direction. In suchexamples, the path is such that the robot cleans the window surface in asingle continuous forwards movement. Optionally, the path startsadjacent the top of the window and finishes adjacent the bottom of thewindow. Suitably, the distance sensor(s) is directed generally in saidforwards direction.

In some examples, the path is defined in the programming of the one ormore processors such that the path comprises a plurality of parallelfirst segments, each of which preferably extends from a positionadjacent one edge of the window to a position adjacent the opposite edgeof the window surface and more preferably extends across substantiallythe whole of the window surface. In one example, the path is defined inthe robot's programming such that said first segments are orientedvertically. In another example, the path is defined in the robot'sprogramming such that said first segments are oriented horizontally.

Suitably, the path is defined in the programming of the one or moreprocessors such that the path further comprises a series of secondsegments, each of which links together two of said first segments.

In one series of examples, the path is defined in the programming of theone or more processors such that said second segments are turningsegments, where the robot carries out a generally smooth turn. The pathmay optionally be defined in the programming of the one or moreprocessors such that the robot begins each of said turning segments whensaid distance sensor(s) indicates it is a predetermined distance, d,from the window frame. In addition or instead, the path may be definedin the programming of the one or more processors such that the robotends each of said turning segments when said orientation sensor(s)indicates that the robot is parallel to the direction of said firstsegments.

In another series of examples, the path is defined in the programming ofthe one or more processors such that said second segments areperpendicular to said first segments. The path may optionally be definedin the programming of the one or more processors such that the robotbegins each of said second segments when said distance sensor(s)indicates it is a predetermined distance, d, from the window frame.

In some examples, the robot further comprises at least one windowpresence sensor(s), which is configured to detect the presence of thewindow adjacent a portion of the robot. Suitably, the movement systemhas a forwards direction and said window presence sensor(s) is arrangedsuch that it detects the presence of the window adjacent a portiontowards the forward end of the robot. The one or more processors mayoptionally be programmed to navigate based on measurements provided bysaid orientation sensor(s), said distance sensor(s) and said windowpresence sensor.

In some examples, the one or more processors may be further programmedsuch that, in the case where the robot is moving and, because the framedoes not extend around the whole of the window, the measurement fromsaid distance sensor(s) is erroneous and, as a result, the robotcontinues to the edge of the window, the one or more processors respondto said window presence sensor(s) indicating that the window is notadjacent said portion of the robot by causing the robot to carry out arearwards movement away from the window edge. The rearwards movementmay, for example, be for a predetermined distance. The one or moreprocessors may optionally be further programmed such that, once saidrearwards movement is complete, they cause the robot to continue movingalong said path. In addition, or instead, the one or more processors maybe further programmed to measure a distance L corresponding to one ormore of said first segments and to cause the robot to begin each of saidsecond segments when it has travelled a distance I since the precedingsecond segment, where I is greater than or equal to L, preferablywherein I is greater than L by a predetermined amount. Hence orotherwise, the robot may further comprise at least one sensor operableto sense the relative motion of the robot (for example: an odometer; anaccelerometer; and/or a gyroscope). The one or more processors mayoptionally be further programmed to measure the distance L correspondingto one or more of said first segments using said sensor(s) operable tosense the relative motion of the robot. The one or more processors mayoptionally be further programmed to measure the distance travelledduring said rearwards movement.

In a still further aspect, the following disclosure describes awindow-cleaning robot including a movement system, configured to movethe robot over a window surface and, thereby, to enable the robot toclean the window surface, the movement system having a forwardsdirection and comprising: a first and a second set of wheels configuredto contact the window surface, each of said wheels being rotatable abouta corresponding axis, said axes being parallel to a width direction,which is perpendicular to said forwards direction, said first set ofwheels being spaced apart from said second set of wheels in said widthdirection; and at least one motor for driving said wheels, said wheelsthereby propelling the robot over the window surface; wherein the wheelswithin each of said first and said second sets are mechanically linkedsuch that rotation of any one wheel within a set causes movement of theother wheels within that set.

The robot may optionally further comprise one or more support membersconfigured to contact the window surface, said one or more supportmembers being spaced apart from said first set of wheels and from saidsecond set of wheels in said forwards direction. Optionally, the atleast one support member comprises a rotatable member, for example anundriven wheel, said undriven wheel is, for instance, configured suchthat its axis of rotation pivots freely about an axis perpendicular tosaid width and said forwards directions.

In some examples, the wheels within each of said first and second setsare aligned in said forwards direction.

Optionally, the at least one motor includes a first motor for drivingsaid first set of wheels and a second motor for driving said second setof wheels.

The robot may optionally further comprise one or more common gears foreach of said first and said second sets of wheels, wherein the wheelswithin each of said first and said second sets of wheels aremechanically linked by the corresponding one or more common gears, whichassist in transferring rotation from the respective one of said firstand said second motors.

In some examples, the robot may further comprise an attachment system,which maintains the robot in contact with the window by producing anattachment force perpendicular to the window surface, preferably whereinsaid attachment force is provided by suction generated by the attachmentsystem. Optionally, the attachment force causes each wheel to deform,thus increasing the contact area between the window surface and thewheel in question.

In a still further aspect, the following disclosure describes a windowcleaning robot comprising: one or more processors; a movement system,configured to move the robot over the surface of a window and, thereby,to enable the robot to clean the window surface; wherein the one or moreprocessors are programmed to operate in a “full cleaning” mode, wherethe robot is caused to separately carry out an interior movement patternand a perimeter movement pattern, so as to clean substantially theentire surface of the window; wherein, said perimeter movement patternis defined in the programming of the one or more processors such thatthe robot carries out at least one circuit of the perimeter of thewindow surface, thus cleaning a strip of the window surface that extendsaround the perimeter of the window surface and is bounded by the edge ofthe window surface; and wherein said interior movement pattern isdefined in the programming of the one or more processors such that therobot cleans the area located within said strip of the window surface.

In some examples, the interior movement pattern may be defined in theprogramming of the one or more processors such that the robot follows ascanning path. The scanning path may, for example, not cross itself.

Suitably, the movement system has a forwards direction. The scanningpath may, for example, be such that the robot cleans the window surfacein a single continuous forwards movement. In addition, or instead, thescanning path may start adjacent the top of the window and finishadjacent the bottom of the window.

In some examples, the interior movement pattern may be defined in theprogramming of the one or more processors such that the scanning pathcomprises a plurality of parallel first segments, each of whichpreferably extends from a position adjacent one edge of the window to aposition adjacent the opposite edge of the window surface and morepreferably extends across substantially the whole of the window surface.In one example, the path is defined in the programming of the one ormore processors such that said first segments are oriented vertically.In another example, the path is defined in the programming of the one ormore processors such that said first segments are oriented horizontally.

Suitably, the interior movement pattern is defined in the programming ofthe one or more processors such that the path further comprises a seriesof second segments, each of which links together two of said firstsegments. In one series of examples, the interior movement pattern isdefined in the robot's programming such that said second segments areturning segments, where the robot carries out a generally smooth turn;the robot may, for example, begin each of said turning segments when therobot is a predetermined distance, d, from the window frame; the robotmay, for instance, end each of said turning segments when saidorientation sensor(s) indicates it is parallel to the direction of saidfirst segments. In another series of examples, the interior movementpattern is defined in the robot's programming such that said secondsegments are perpendicular to said first segments; the robot may, forexample, begins each of said second segments when the robot is apredetermined distance, d, from the window frame.

In still another aspect, the following disclosure describes awindow-cleaning robot comprising: a movement system, configured to movethe robot over a window surface; one or more cleaning pads, configuredto be wetted with a cleaning fluid and to contact the window surface soas to remove debris therefrom with the aid of the cleaning solution; andone or more polishing pads configured to contact the window surface and,thereby, to polish it when the robot is moved over the window surfaceusing said movement system, each polishing pad polishing the windowsurface such that any layer of cleaning fluid present on the windowsurface is left as a thinner layer and/or is dispersed over a greaterarea after the polishing pad passes over it.

In some examples, the movement system has a defined forwards directionand said one or more cleaning pads are arranged such that, as the robotmoves over the window surface in said forwards direction, they togetheraddress a first width in a width direction, which is perpendicular tosaid forwards direction and parallel to the window surface. Eachcleaning pad may, for example, be elongate in said width direction.Optionally, the one or more polishing pads are arranged such that, asthe robot moves over the window surface in said forwards direction, theytogether address a second width in said width direction, said secondwidth being substantially equal to said first width.

The one or more polishing pads may for example comprise a rearwards oneor more polishing pads, said one or more cleaning pads being locatedbeyond said first one or more polishing pads in said forwards direction.The one or more polishing pads may additionally comprise a forwards oneor more polishing pads, which are located beyond said cleaning pads insaid forwards direction. The forwards one or more polishing pads may besubstantially the same as said rearwards one or more polishing pads.

In some examples, the robot may further comprise one or more reservoirsfillable with cleaning fluid, the one or more reservoirs beingfluidically connected so as to supply said cleaning fluid to said one ormore cleaning pads.

Optionally, each cleaning pad comprises a cloth that is wettable by saidcleaning fluid, said cloth may for example be a microfiber cloth. Eachpolishing pad may optionally comprise a cloth that is wettable by saidcleaning fluid. Each cleaning pad cloth and each polishing pad cloth maybe formed of fibers, with the fibers of said cleaning pad cloths beingsubstantially finer than those of the polishing pad cloths.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings, inwhich:

FIG. 1 illustrates schematically an example of a robotic window cleanerand the systems thereof;

FIG. 2 is a plan view of the side of a window-cleaning robot thatattaches to the surface of a window;

FIG. 3 is a cross-sectional side view of the robot of FIG. 2;

FIG. 4A is a perspective view of the robot of FIGS. 2 and 3 with its topcover removed so as to display various of the robot's internalcomponents;

FIG. 4B is a perspective view of the robot of FIGS. 2 and 3 with the topcover in place;

FIG. 5 is a view of a cross-section through the impeller-based vacuumpump of the robot of FIGS. 2 to 4;

FIG. 6A is a perspective view of the sealing foil of the robot of FIGS.2 to 4;

FIG. 6B is a perspective view of a cross-section through the sealingfoil of FIG. 6A;

FIG. 7A is a side view of a cross-section through the robot of FIGS. 2to 4, illustrating the location of the sealing foil with respect toother components of the robot;

FIG. 7B is a detail view of FIG. 7A that illustrates the configurationof the sealing foil prior to engagement with the window surface;

FIG. 7C is a detail view of FIG. 7A that illustrates the configurationof the sealing foil when engaged with the window surface;

FIG. 8A is a perspective view of one of the suction cups of the robot ofFIGS. 2 to 4, taken from the side opposite that which engages with thewindow surface;

FIG. 8B is a perspective view of the suction cup of FIG. 8A, taken fromthe side that engages with the window surface;

FIG. 9 is a perspective view of a cross-section through the suction cupof FIGS. 8A and 8B;

FIG. 10A-10C are perspective views of the suction cup of FIGS. 8 and 9in cross-section, taken at various stages of the suction cup'sengagement with a window surface;

FIG. 11 is a plan view of the cleaning pad member of the robot of FIGS.2 to 4, taken from the side which engages with the window surface;

FIG. 12 is a perspective view of the rear section of the robot of FIGS.2 to 4 that illustrates an arrangement used to mount cleaning pad memberto the main body of the robot;

FIG. 13A is a perspective view of the cleaning pad member and robotchassis with various components removed to illustrate the mountingarrangement for the cleaning pad member;

FIG. 13B is a perspective view of a cross-section through the cleaningpad member;

FIG. 13C is a perspective view of a cross-section through the cleaningpad member and the mount therefor provided on the main body of therobot;

FIG. 14A is a plan view of the robot of FIGS. 2 to 4 carrying out a turnadjacent the frame of the window;

FIGS. 14B(i)-14B(iv) are plan views of the robot of FIGS. 2 to 4 atrespective points in the turn illustrated in FIG. 14A;

FIG. 15 is a plan view of the robot of FIGS. 2 to 4 navigating over thesurface of a window along a path including a number of parallel verticalsegments, which are connected by smooth turns;

FIG. 16 is a plan view of the robot of FIGS. 2 to 4 navigating over thesurface of a window along a path including a number of parallel verticalsegments, which are connected by short horizontal paths;

FIG. 17 illustrates the behavior of a robot moving over a window thathas a frame that extends around only a portion of the window's edge;

FIG. 18 illustrates the robot of FIGS. 2 to 4 following a similar pathto that shown in FIG. 15, but with parallel horizontal segments;

FIG. 19 illustrates the robot of FIGS. 2 to 4 carrying out a perimetermovement pattern;

FIG. 20 illustrates the strip of the window surface cleaned by the robotwhen carrying out the perimeter movement pattern illustrated in FIG. 19;

FIG. 21A is a perspective view of one of the two sets of wheels of therobot of FIGS. 2 to 4, together with the associated drive components;

FIG. 21B is a perspective view of the wheels and drive components ofFIG. 21A, with the housing not shown so as to more clearly illustratethe drive components; and

FIG. 21C is a perspective view of the wheels and wheel mount of FIG.21A.

DETAILED DESCRIPTION

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings. The invention is capable of otherembodiments or of being practiced or carried out in various ways.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method, with various computercomponents. The computer components may be in the form of hardwareembodiment, software (including firmware, resident software, micro-code,etc.) or an embodiment combining software and hardware aspects that mayall generally be referred to herein as a “circuit”, “module” or“system.”.

Turning now to FIG. 1, there is shown schematically an example of awindow-cleaning robot 10, in which various aspects of the presentinvention may be embodied, and details the systems included therein. Asis shown in the drawing, the robot 10 includes: a movement system 400,for moving the robot over the surface of the window; a navigation system300, to enable to robot to navigate around the surface of the window; anattachment system 600, to enable the robot to attach itself to thewindow surface (and to keep it attached thereto); a cleaning system 500,for removing dirt, debris and the like from a portion of the windowsurface adjacent the robot, as the robot moves over the window surface;a power system 200, for powering the various systems, components etc.within the robot; a control system 110, for communicating with andcontrolling the systems of the robot; and a user interface 700, enablingthe user to input commands, information and the like to control therobot's operation and providing an indication to the user of the robot'scurrent state.

The control system 110 may, for example, include a main board, and allelectronics, as hardware, software and combinations thereof and othercomponents, necessary for the robot 10 to perform all of its operationsand functions (known as the main board electronics). The main boardincludes one or more processors 101 as part of the main boardelectronics.

As indicated in the drawing with solid lines, the navigation, movement,attachment, cleaning, power and user interface systems are in datacommunication with the control system, so that the control system canreceive data from and/or send instructions to these systems.

The power system 200 may, for example, include: an internal powersupply, including one or more batteries (typically rechargeable);battery voltage sensors, typically for each battery, that enable therobot to determine when the power supply is running low; and chargingcontacts, that enable electrical connection to an external power sourceso as to allow the internal power supply to be charged. The chargingcontacts may be connectable to an electrical lead that is connectable,for instance with standard plug, to an external power supply, such as amains power supply; the lead may include a transformer, whereappropriate.

As discussed above, the power system 200 may have a data connection tothe control system 110 so that the control system can receive data fromthe power system, for example relating to the current power level of theinternal power supply (e.g. using battery voltage sensors).

The robot 10 may be designed such that it can be received by a dockingstation (not shown) which the robot 10 will return to once its task iscomplete (e.g. for orderly control and arrangement of the robot), and/orwhen its internal power supply is running low. While in this dockingstation, various functions can occur, such as battery recharging (e.g.by means of charging contacts) and the like.

The power system 200 may, instead of having an internal power supply (orin addition to having an internal power supply) rely on power from anexternal power supply, such as the mains power supply. Where the powersystem relies solely on power from an external power supply, chargingcontacts may not be included, but the power system 200 may nonethelessinclude an electrical lead connectable to an external power source; suchan electrical lead may be built-in to the robot 10, so that it cannot beremoved by the user and will not detach during normal operation.

As shown by dotted lines in FIG. 1, the power system is electricallyconnected to the control, navigation, movement, cleaning and attachmentsystems, and the user interface, so as to supply electrical power tothese systems and their components.

The navigation system 300 may include a number of sensors that enablethe robot to navigate around the surface of the window, when movingusing the movement system 400. For instance, the navigation system 300may include: sensors that enable the robot to determine its currentdistance from the window frame (which will typically extendperpendicular to the window surface); sensors that enable the robot todetect the presence of the window surface adjacent a portion of therobot; sensors that enable the robot to determine its currentorientation (e.g. with respect to gravity or a predeterminedorientation). As shown in FIG. 1, the navigation system 300 is in datacommunication with the control system 100. The control system 100 maytherefore receive data from the navigation sensors and control themovement system 400 in dependence upon such data.

As noted above, the attachment system 600 enables the robot to attachitself to the window surface and keeps it attached thereto. Theattachment system 600 may, for example, utilise suction forces to attachthe robot to the window surface. Accordingly, it may, for instance,include one or more vacuum pumps to provide a suction force and one ormore sealing members that contact the window surface so as to seal aspace between the robot and the window surface, with the vacuum pump(s)being configured to reduce the air pressure in this space.

The attachment system 600 might instead (or in addition) utilisemagnetic forces to attach the robot to the window surface. Accordingly,the user may be provided with a paired device that is placed on theopposite surface of the window to the side on which the robot operates,with the robot and the paired device being magnetically attracted toeach other. Hence, the robot and/or the paired device may, for instance,include one or more magnetic members, such as electromagnets orpermanent magnets.

As shown in FIG. 1, the attachment system 600 is in data communicationwith the control system 100 and may therefore receive commands from thecontrol system 100 and send status information to the control system100. For example, the control system 100 may command the attachmentsystem 600 to increase the attachment force.

The movement system 400, as noted above, enables the robot to move overthe surface of the window. Accordingly, it may, for instance, includewheels, tracks and the like that contact the window surface and apply aforce thereto so as to drive the robot over the window surface. As shownin FIG. 1, the movement system 400 is in data communication with thecontrol system 100 and may therefore receive commands from the controlsystem 100. For example, the movement system 400 may be commanded by thecontrol system to move the robot along a path calculated by theprocessor(s) 101 within the control system 100.

In some arrangements, the movement 400 and attachment 600 systems may becombined, such as where a number of elements each provide a separateattachment force and are moveable with respect to each other. Oneexample of such a combined attachment and movement system is where twoor more separate sealing elements are provided that are moveable withrespect to each other; each of the sealing elements may be provided witha dedicated vacuum pump in such a situation.

The cleaning system 500, as noted above, removes dirt, debris and thelike from a portion of the window surface adjacent the robot, as therobot moves over the window surface, using the movement system 400. Thecleaning system may include, for example, a cleaning pad that is wettedwith cleaning fluid, a reservoir for cleaning fluid, a water hose.Although in FIG. 1 the cleaning system 500 is shown as being inelectrical communication with power system 120 and in data communicationwith control system 100, in some arrangements, the cleaning system mightinclude no powered components, in which case, such connections to thepower 200 and control 100 systems would be unnecessary. In somearrangements, the cleaning system 500 may be combined with theattachment system 600, for example, where a suction force is appliedthrough a cleaning pad. In further arrangements, the cleaning 500,attachment 600 and movement 400 systems might all be combined, forexample where a number of cleaning pads are provided that may moverelative to one another, with a suction force being applied through eachcleaning pad.

Turning now to the user interface 700, as noted above, this may enablethe user to input commands, information and the like to control therobot's operation and may provide an indication to the user of therobot's current state. Accordingly, it may include a number of controls,such as buttons, dials and the like, and a number of indicators, such asa display screen, LEDs and the like, or a combination of both, such as atouchscreen. It may also include a wireless communication link, so as toconnect with a user device, such as a smart-phone, tablet device,laptop, PC etc.

As shown in FIG. 1, the user interface 700 is in data communication withthe control system 100. The user interface 700 may therefore receivestatus information from the control system 100 that it then displays orindicates to the user. Conversely, the control system 100 may receiveuser commands that are inputted using the user interface 700 and may,thereafter, send corresponding commands, for instance, to the movement400, attachment 600 and cleaning 500 systems. For example, the user mayuse the user interface 700 to select one of a number of operation modesthat the robot (specifically the processor(s) of the control system 100)has been programmed with and the control system 100 may thereaftercommand, for instance, the movement 400, attachment 600 and cleaning 500systems in accordance with rules and procedures that are associated withthe mode selected by the user.

Attention is now directed to FIGS. 2 to 4, which illustrate a morespecific example of a window-cleaning robot 1 that includes control 100,power 200, navigation 300, movement 400, cleaning 500 and attachment 600systems and a user interface 700, which generally interact in the mannerdescribed above with reference to FIG. 1.

The robot 1 shown in FIGS. 2 to 4 is configured such that its movementsystem 400 has a defined forwards direction, which is indicated by arrowF in FIG. 2. In the specific example shown, the forwards direction isperpendicular to the axes of rotation of the wheels 421A-422A,421B-422B, as well as being parallel to the window surface, though withother movement systems 400 the forwards direction may be defined indifferent ways (e.g. in a system that uses continuous tracks, it may beparallel to the length direction of each such track).

The forwards direction F defines a “forwards” end for the robot 1; thisis the uppermost end in FIG. 2, which is a plan view of the side of awindow-cleaning robot that attaches to the surface of a window. Bycontrast, the lowermost end in FIG. 2 is the “rearwards” end.

FIG. 2 also indicates, using arrow W, a width direction for the robot,which is perpendicular to the forwards direction F and which is parallelto the window surface when the robot is attached thereto.

The forwards direction F may, for example, be distinguished from theopposite, rearwards direction in terms of the rules and policies bywhich the control system 100 operates the movement system 400. Forinstance, such rules and policies may be such that the robot 1 will movein the forwards direction D (upwards in FIG. 2, though not necessarilyupwards with respect to gravity) with significantly greater regularitythan in the opposite, rearwards direction (downwards in FIG. 2, though,similarly, not necessarily downwards with respect to gravity).

As may also be seen from FIG. 2, in terms of its structure by the robot1 has fairly distinct front, middle and rear sections.

In the specific example of a robot shown in FIG. 2, the middle sectionprovides many of the components for the attachment system 600 and themovement system 400 of the robot 1.

In more detail, the middle section includes a sealing member 610, whichcomprises a thin foil surrounding seal, and a vacuum pump, which, in theexample shown, is based on a double rotating impeller 630. The inlet forthe impeller 630 near-most the window surface is clearly visible in FIG.2. The double impeller 630 is shown in greater detail in FIG. 5, whichis a view of a cross-section through the impeller-based vacuum pump. Asmay be seen in the drawing, the impellers 630A, 630B are arrangedcoaxially, with one impeller located directly over the other. Theimpeller-based vacuum pump further includes a motor 635, which drivesthe impellers 630A, 630B by means of shaft 636, causing them to rotateabout an axis that is generally perpendicular to the window surface.Such a double-stage impeller may be efficient both in term of space andalso power, thus reducing power consumption, as well as generatinglittle noise. However, a single impeller or multiple impellers could beemployed instead.

The sealing member 610 and the impeller-based vacuum pump both form partof a suction-based attachment system 600 for the robot.

The middle section further includes two sets of drive wheel pairs421A-422A, 421B-422B, where the wheels of each pair are driven with thesame transmission and thus move at the same velocity, as well as castorwheels or sliding points 450A, 450B. In the particular example of arobot shown, wheels 421A-422A, 421B-422B are covered by a soft tire (forexample, formed of rubber or polyurethane) with a high frictioncoefficient in respect of glass. The drive wheel pairs 421A-422A,421B-422B and castor wheels or sliding points 450A, 450B form part of amovement system 400 for the robot shown in FIG. 2.

As may be seen from FIG. 3, which is a cross-sectional side view of therobot 1 of FIG. 2, the robot includes a chassis 13, which supportsand/or contains many of the components of the robot. As is also shown inFIG. 3, the drive wheels 421A-422A, 421B-422B and castor wheels orsliding points 450A, 450B form a plane which is about 1-2 mm from thesurface of the chassis 13 that is near-most the window surface. Thesealing foil 610 (which is shown in greater detail in FIGS. 6 and 7) ismounted on the chassis 13 in a manner that closes this gap and thusseals a space, or chamber, between the robot and the window surface. Theimpeller 630 may then remove air from this space, thus creating a vacuumwhich attaches the robot 1 to the window surface. The attachment forcecreated by this vacuum squeezes the tires against the window surface,thus increasing the area over which the wheels 421A-422A, 421B-422Bcontact the window surface, accordingly providing the wheels with a goodgrip on the window surface.

More particularly, to assist the robot in travelling over the window,the attachment system 600, for example using the impeller-based vacuumpump 630, generates an attachment force that provides sufficientfriction between the wheels 421A-422A, 421B-422B of the movement system400 and the window surface for the robot 1 to be moved over the windowsurface without slipping. For example, where the robot is orientedvertically, the attachment system 600 may need to provide sufficientattachment force such that the wheels 421A-422A, 421B-422B havesufficient friction to exceed the gravitational force applied on therobot 1.

As the robot 1 moves over the window surface using the movement system400, the sealing foil 610 slides on the window. The impeller-basedvacuum pump 630 maintains a vacuum within the space sealed by thesealing foil 610; to do so, they may need to generate continuous flow ofair, as some air will typically be lost as a result of the movement ofthe sealing foil 610 over the window surface. This may be particularlythe case where the window is uneven or is especially dirty.

The structure of the sealing foil 610 of the robot of FIGS. 2 to 4 isshown in further detail in FIGS. 6 and 7. As may be seen from FIG. 6A,which is a perspective view of the sealing foil 610, the sealing foil610 is generally rectangular in shape and has a top portion 611 that isjoined to the robot (specifically, to the chassis 13) and a bottomportion 612 that is configured to engage with the window surface. As maybe seen from FIG. 6B, which is a perspective view of a cross-sectionthrough the sealing foil 610, the bottom 612 portion is configured as askirt, which flares outwards and downwards, whereas the top portion 611extends generally upwards. As is also visible in FIG. 6B, the sealingfoil 610 is a thin (e.g. around 0.25 mm) film of plastic. The sealingfoil 610 may be formed of a material that has low friction when incontact with glass.

FIG. 7A, which is a side view of a cross-section through the robot 1,shows the location of the sealing foil 610 with respect to othercomponents of the robot 1. The shape of the sealing foil 610 prior toengagement with the window surface 1000 is visible in FIG. 7B, which isa detail view of the robot 1 that shows the configuration of the sealingfoil 610 prior to engagement with the window surface 1000. It shouldhowever be noted that in FIG. 7B the robot—with the exception of thesealing foil—is shown in engagement with the window surface 1000;accordingly, the sealing foil 610 is shown as extending through windowsurface 1000, whereas other features of the robot, such as wheels421A-422A, 421B-422B, are shown engaged with the window surface 1000.

FIG. 7C is a corresponding detail view of the robot 1 that shows theconfiguration of the sealing foil 610 when engaged with the windowsurface 1000. As in FIG. 7B, the wheels 421A-422A, 421B-422B of themovement system in contact with the window surface 1000. As may be seenfrom FIG. 7C, the sealing foil 610 generally touches the window only atits tip. This may reduce the amount of friction it creates as the robotmoves over the window surface 1000. The shape of the sealing foil 610may be such that the vacuum forces increase the contact area with thewindow surface 1000, thus improving the sealing. For instance, thebottom portion of the sealing foil 610 may flatten against the windowsurface 1000 as the pressure is reduced within the space sealed bysealing foil 610.

Returning now to FIG. 2, the middle section of the robot furtherincludes two suction-cups 620A, 620B, which may provide a low-power“parking” mechanism, for instance for when the robot 1 is operating in a“paused” mode, where it does not move over the window surface 1000.These suction cups 620A, 620B are normally at the chassis surface level(for example so that they do not contact the window surface 1000 andthus generate additional frictional resistance to movement), but may bemoved towards the window surface 1000 under the control of the controlsystem 100, with a vacuum then being created within the space sealed byeach suction-cup 620A, 620B using a vacuum pump 640.

As may be seen from FIG. 4A, which is a perspective view of the robot 1with its top cover 11 removed so that several of the internal componentsare visible, the vacuum pump 640 for the suction-cups 620A, 620B isseparate from the double-impeller vacuum pump 630 that reduces the airpressure in the space sealed by the sealing foil. Further, the vacuumpump 640 for the suction-cups 620A, 620B may be of a different type tothat for the sealing foil 610; for instance it may be a diaphragm vacuumpump. In the robot of FIGS. 2 to 4, a single vacuum pump 640 is sharedbetween the two suction-cups 620A, 620B (the pipes 641 linking thisvacuum pump 640 to the suction-cups 620A, 620B are clearly visible inFIG. 4A); however, it will be apparent that a dedicated vacuum pumpcould be provided for each suction-cup 620A, 620B.

As is shown in FIG. 2, each suction cup 620A, 620B has a hole 623 in itssurface that communicates with a pressure sensor for sensing thepressure adjacent the suction cup 620A, 620B, in the space between thesuction cup and the window surface 1000. These pressure sensors may forma further part of the attachment system 600. When the suction cup 620A,620B is brought into contact with the window surface 1000 and seals aspace between the robot and the window surface 1000, the pressure sensorenables the robot (specifically the control system 100) to determine thelevel of the vacuum in the thus-sealed space.

The front section of the robot, which is the uppermost section in FIG.2, includes a powered agitator 510. In the specific example shown, thepowered agitator is an agitating bristle brush that is driven by ageared motor 515, which is visible in FIG. 4A. More particularly, theagitator 510 rotates about an axis that is parallel to the windowsurface and to width direction W. This agitator 510 forms a part of thecleaning system 500 for the robot 1. As will be discussed in furtherdetail below, the agitator 510 mechanically removes debris from thewindow surface 1000. In certain arrangements, it may be arranged so asto provide an initial heavy-duty dry cleaning of the window surface 1000(“dry” in the sense that it may be arranged so as to be spaced apartfrom any sources of liquid, such as cleaning fluid or water). Theagitator 510 may be driven at high speed, for example rotating at around600 RPM. As the agitator 510 is located at the front of the robot 1, itwill generally be applied to the window surface 1000 first as the robot1 moves over the window surface 1000.

As indicated in FIG. 4A, the front section additionally includes windowsurface proximity sensors 320A, 320B, 320C and distance sensors 310A,3108; in the specific example shown, these sensors are provided on thehousing for the agitator 510. These proximity and distance sensors forma part of the navigation system 300 for the robot.

The proximity sensors 320A, 320B, 320C enable the control system 100 todetermine whether the window surface 1000 is present adjacent a portionof the robot 1 (e.g. adjacent a portion of the side that is configuredto engage with the window surface 1000). In addition, the control system100 is able to use the proximity sensors 320A, 320B, 320C of thenavigation system 300 to determine that a portion of the robot 1 hasmoved beyond the edge of the window surface, for example in the case ofa frameless window.

As will be discussed in more detail below, the control system 100 maycontrol the attachment system 600 based on the output from the proximitysensors 320A, 320B, 320C. For example, the control system 100 may onlyactivate the attachment system when the proximity sensors 320A, 320B,320C indicate that the robot 1 is adjacent the window surface 1000.

Various types of proximity sensors 320A, 320B, 320C can be used, such asthose based on detecting reflected light or infra-red radiation,reflected ultrasound, and the like. For quantitative proximitymeasurement, time-of-flight based sensors may be used; these maysimilarly be based on reflected infra-red, light, ultrasound and thelike. A particular example of a suitable time-of-flight sensor is theVL6180 optical time-of-flight sensor, supplied by ST Microsystems.

The distance sensors 310A, 310B may be such quantitative proximitysensors and may therefore be time-of-flight sensors (e.g. VL6180 opticaltime-of-flight sensors). The distance sensors 310A, 310B may be arrangedso as to be forwards looking and may, therefore, be mounted at the frontof the robot 1. For instance, they may be located on top of (as shown inthe example of FIG. 4A) or in front of the agitator 510. The distancesensors 310A, 310B enable the control system 100 to determine therobot's current distance from the frame for the window. Such distancemeasurements allow the control system 100 to plan the robot's scanningtrajectory, with the movement system 400 being directed by the controlsystem 100 to carry out the scanning trajectory.

As may be seen from FIG. 2, the rear section of the robot, which is thelowermost section in FIG. 2, includes a cleaning pad member 550 thatprovides a cleaning pad 520 and a pair of polishing pads 530A,530B, oneeither side of the cleaning pad 520. As the cleaning pad 520 is at therearwards end of the robot, it will generally be applied to the windowsurface 1000 after the agitator 510, as the robot moves over the windowsurface 1000 in the forwards direction F.

As is apparent from FIG. 2, the cleaning pad 520 addresses a width W_(C)in the width direction W that is substantially the same as the widthW_(A) addressed by the agitator 510. Therefore, areas of the windowsurface 1000 addressed by the cleaning pad 520 will generally alreadybeen addressed by the agitator 510. As will be discussed in more detailbelow, this may provide a more effective clean of the window surface1000 and/or may extend the lifetime of the cleaning pad 520.

As may also be seen from FIG. 2, the cleaning pad 520 is elongate in thewidth direction W. This may provide a more compact structure for therobot 1.

The cleaning pad member 550 may be moveably mounted on the main body 10.In the particular example shown in FIGS. 2 to 4, the cleaning pad member550 of the robot 1 of FIGS. 2 to 4 is spring-loaded and free to moveright/left in the width direction W, with respect to the chassis 13 ofthe robot 1 and thus with respect to the main body 10 of the robot 1.

As will be discussed in further detail below with reference to FIGS. 11to 14, such an arrangement may allow embodiments of the robot 1 to drivenext to the window frame, cleaning the window surface 1000 all the wayto its edge without the robot body 10 touching the frame 1010. Such anarrangement may additionally (or instead) allow the robot to turn whileit is near the frame 1010, as shown in FIG. 14. As the discussionfurther below notes, the cleaning pad may be moveably mounted on themain body of a robot in various ways: the construction shown in FIGS. 2to 4 is simply one example of a way of achieving this.

As will also be discussed below with reference to FIGS. 11 to 14, thecleaning pad 520 may be mounted such that, during use, it is pressedagainst the window surface. This may assist in more effectively cleaningthe window surface.

Furthermore, the cleaning pad 520 may, for example, be composed of amicrofiber cloth. The microfiber cloth may be kept wet with a cleaningfluid that dissolves the salts, debris and oil stains on the surface. Areservoir containing cleaning fluid may be provided within the robotadjacent the cleaning pad 520 (for example, within the cleaning padmember) and may be configured to supply cleaning fluid to the cleaningpad 520. Alternatively, the user may apply cleaning fluid to thecleaning pad 520, for example by spraying the fluid onto the cleaningpad using a spray bottle. As a still further alternative, the robotmight apply cleaning fluid directly to the window surface 1000, forinstance at positions adjacent the cleaning pad 520, so that thecleaning pad will be wetted by the cleaning fluid shortly afterapplication to the window surface 1000.

In the robot shown in FIGS. 2 to 4, the rear section further includestwo elongate polishing pads 530A, 530B, as is perhaps best illustratedin FIG. 2.

As is apparent from FIG. 2, each of these polishing pads 530A, 530Baddresses the same width W_(C) as the cleaning pad 520, so that theareas of the window surface 1000 addressed by the cleaning pad 520 aregenerally also addressed by the polishing pads 530A, 530B.

As is also apparent from FIG. 2, each of the polishing pads 530A, 530Bis elongate in the width direction W; this may assist in providing therobot 1 with a compact structure. In the particular example shown, thepolishing pads 530A, 530B are narrower than the cleaning pad and extendparallel to the length of the cleaning pad and to each other, and aredisposed on either side of the cleaning pad.

The polishing pads 530A, 530B act to thin the layer of cleaning fluidleft on the window surface 1000 by the cleaning pad 520, so that itdries evenly, thus providing a good finish. The polishing pads may beconfigured so as to be pressed against the window surface 1000 with ahigher force than the cleaning pad.

As will be discussed in greater detail below, the robot 1 may moveacross and clean the window surface 1000 according to variousstrategies. For example, it may scan the vast majority of the windowsurface, except for a perimeter portion of the window surface adjacentthe edge of the window, using an up/down or right/left repeating patternas shown, respectively, in FIGS. 15-17 and 18. It may then cover theperimeter portion of the window surface by carrying out a circuitadjacent the window edge, as shown in FIG. 19.

As is also shown in FIGS. 3 and 4A, the rear section further includesbatteries 220A-220C, which are provided within a battery housing as partof a battery module 210. The batteries 220A-220C will typically berechargeable batteries, such as rechargeable Lithium ion batteries. Thebattery module 210 containing the batteries 220A-220C may be detachable,for instance to allow charging of the batteries 220A-220C containedtherein and/or to allow it to be substituted for an extra battery modulein the user's possession (e.g. a battery module that the user hasalready charged).

Attention is now directed to FIG. 4B, which is a perspective view of therobot of FIGS. 2 and 3 with the top cover in place. As may be seen fromFIG. 4B, a handle is 12 provided by the robot 1, which allows the userto more easily carry the robot 1 to the window and hold it while itattaches to the window surface 1000. In the robot 1 illustrated in FIGS.2 to 4, this handle 12 is part of the top cover 11 for the robot 1.

Various user interface features may suitably be provided on the handle12. For instance, a “play/pause” button 710 may be provided on thehandle. This “play/pause” button switches the robot 1 between a “paused”mode, where it remains stationary on the surface of the window, and auser-selected one of a number of “active” modes, which have beenprogrammed into the processor(s) 101 of the control system 100 and inwhich the moves, using the movement system 400, over the surface of thewindow. In addition or instead, the handle may contain a “release”button 720, which assists the user in removing the robot 1 from thewindow surface 1000. When depressed, the “release” button 720 causes theattachment system 600 to deactivate, such as by turning off theimpellers 630 and/or disengaging the suction cups 620A, 620B from thewindow surface 1000.

Around the “play/pause” button 710 there may also be provided a numberof indicators (e.g. LEDs) that provide the user with information aboutthe current status of the robot, such as the current operation mode andbattery status. The “play/pause” button, the “release” button 720 andthese light indicators may each form a part of the user interface 700for the robot 1 shown in FIGS. 2-4.

FIG. 4A also shows the main board 110 of the robot, which contains oneor more processors (e.g. one or more microprocessors) and drivers forthe various motors. These components may form part of the control system100 for the robot. The main board 110 may additionally includenavigation sensors, such as an accelerometer, a gyroscope (for measuringthe robot orientation) etc. as well as air pressure sensors. It will ofcourse be appreciated that these sensors could instead be providedremotely from the main board 110, in which case suitable electricalconnections to the main board may be provided.

Cleaning System Including an Agitator and Cleaning Pad

The following section of the disclosure relates to the cleaning systemof a robotic window cleaner.

Traditional window cleaning involves the wetting of the surface, forexample with a cleaning solution (usually water with some soap) and thensqueegeeing, in some specific pattern that prevents marks being left onthe window surface (which are usually a result of uneven drying of thewater layer residues). If the window is very dirty, then a pre-wash maybe performed to wash all the dirt/mud off the window; in addition,suction might be used to remove the dirty water. Alternatively, somepapers/cloths may be used to absorb the dirty water. All of these“traditional” methods are less appropriate for a robot cleaner sincethey require, in the case of washing with water, a connection to a watersource or, for the robot itself to carry a water container onboard(which, being heavy, may be a significant drain on power usage and thusbattery life, where the robot is battery powered), or, in the case ofthe use of papers/cloths, the frequent replacement of suchpapers/cloths, thus increasing the amount of user intervention required,which contradicts the labor-saving principle behind robotic systems.

Currently available robotic window cleaners, such as the WinBot and theHobot, use cleaning pads that are wetted either manually by the user orby a dispenser. However, as mentioned above, when a window is reallydirty, this may be ineffective or require frequent replacement of thepads.

In contrast, it is proposed to provide a robot that cleans the windowsurface using at least the following two steps:

-   -   1. Agitating: in this stage, a powered agitator (or several        powered agitators), such as a rotating bristles brush, rotating        pad or other device, excites the dust/debris on the window and        forces it to leave the surface and fall down. This stage may be        carried out in substantially dry conditions (for example, the        agitator may be spaced away from the location(s) where the robot        applies cleaning fluid to the window), thus allowing an easy        removal of the dirt as well as keeping the agitator clean. Thus,        the agitator(s) may be located towards the forwards end of the        robot. In the example robot 1 of FIGS. 2 to 4, the agitator 510        is located forwards of the cleaning pad 520, so that it will        typically be applied to the window surface 1000 prior to the        cleaning pad 520.        -   The removal of the heavy dirt from the window in this way            may reduce the need to collect it in the ways mentioned            above (heavy watering, suction etc.), though these could be            included if desired.        -   Where, as in the example robot of FIGS. 2-4, the attachment            system for the robot is a suction/vacuum-based attachment            system and includes a sealing member (or several sealing            members), these sealing members may be arranged such that            they lie substantially wholly within the width            (perpendicular to the robot's forwards direction) that is            addressed by the agitator(s) and such that they are located            rearwards of the agitator(s). As a result, areas of the            window surface that the sealing member(s) contact will            generally already have been addressed by the agitator(s).            This may improve the seal to the window surface provided by            the sealing member(s), which in turn may increase the            battery life of the robot, since the vacuum pumps may            operate at lower power. This may be particularly beneficial            with sealing members (referred to elsewhere herein as            “active-mode sealing members) that are used to attach the            robot to the window surface while it is moving, such as the            sealing foil 610 of the robot 1 of FIGS. 2 to 4.    -   2. Wetting: in this stage a cleaning pad (or several cleaning        pads), for example including a cloth (such as microfiber type),        wetted with a cleaning solution, runs over the window surface in        order to remove the salts or other sticky debris that could not        be removed in the agitating stage.        -   The cleaning pad(s) are located rearwards of the agitator(s)            and, moreover, the agitator(s) address a width that is            substantially the same as (or greater than) that addressed            by the cleaning pad(s). As a result, areas of the window            surface addressed by the cleaning pad(s) will generally have            already been addressed by the agitator(s). Since the areas            addressed by the cleaning pad(s) will typically have already            been cleaned of heavy dirt, the cleaning pad(s) can            concentrate on removing salts or sticky debris. This may,            for instance, provide a more effective clean of the window            surface and/or may extend the lifetime of the cleaning            pad(s) (since they will have to clean less of the heavy dirt            from the window).        -   It should be noted that the requirement that the agitator(s)            address a width that is substantially the same as (or            greater than) that addressed by the cleaning pad(s), allows            for the width addressed by the cleaning pad(s) to be            slightly greater (e.g. by 5%) than the width addressed by            the agitator(s). An example of this may be seen in the robot            of FIGS. 2 to 4, where the width W_(C) addressed by cleaning            pad 520 is slightly greater than the width W_(A) addressed            by the agitator 510. It will be understood that, with such            minor differences in the width addressed, it will            nonetheless be the case that areas of the window surface            1000 addressed by the cleaning pad(s) will generally have            already been addressed by the agitator(s).        -   In some cases, the agitator may be configured so that debris            that it contacts is swept in such directions as to avoid the            cleaning pad; that debris is swept clear of the cleaning            pad. For instance, in the robot of FIGS. 2 to 4, the            agitator rotates about an axis parallel to the width            direction W in a direction so that the portions contacting            the window surface 1000 are moving generally in the forwards            direction (i.e. the clockwise direction as seen in FIG. 3).        -   A reservoir containing cleaning fluid may be provided within            the robot adjacent the cleaning pad. This reservoir may be            fluidically connected so as to supply cleaning fluid to the            cleaning pad. Alternatively, such a reservoir may be            fluidically connected so as to apply cleaning fluid directly            to the window surface, for instance, at positions forwards            of and adjacent to the cleaning pad, so that the cleaning            pad will be wetted by the cleaning fluid shortly after the            cleaning fluid is applied to the window surface. As a            further alternative, the user may themselves apply cleaning            fluid to the cleaning pad, for example by spraying the fluid            onto the cleaning pad using a spray bottle.        -   The cleaning fluid may act to dissolve the salts, debris and            oil stains on the surface. It may include solvents and/or            soap. In addition, it may include various chemical            components to accelerate the dehydration and break the            liquid surface-tension. This may reduce the incidence of            streak-marks on the window surface.        -   Where, as in the example robot of FIGS. 2-4, the attachment            system for the robot is a suction/vacuum-based attachment            system and includes a sealing member (or several sealing            members), these sealing members may be arranged such that            they are located forwards of the cleaning pad(s), as the            cleaning fluid that the cleaning pad(s) spread over the            window surface may weaken the seal to the window surface            provided by the sealing member(s), which in turn may            decrease the battery life of the robot, since the vacuum            pumps may need to operate at higher power to keep the robot            attached to the window surface. Such an arrangement may be            particularly beneficial with sealing members (referred to            elsewhere herein as “active-mode sealing members”) that are            used to attach the robot to the window surface while it is            moving, such as the sealing foil 610 of the robot 1 of FIGS.            2 to 4.

The cleaning process may additionally include the following, optionalstep:

-   -   3. Polishing: in this stage a polishing pad (or several        polishing pads), for example a more dense cloth(i.e. one with        thicker fibers than those of the cleaning pad, for example a        fabric similar to that used to clean glasses), is run over the        surface. The polishing pad(s) may therefore act to, for example,        further thin the cleaning solution layer (for faster and move        even dehydration) and/or to polish and spread more evenly the        residual cleaning fluid over the surface. As the human eye is        very sensitive to differences, this may further improve the        finish, making the window surface appear more “shiny” to the        user. Hence (or otherwise), polishing pad(s) may be arranged        rearwards of the cleaning pad(s). Further, they may address        substantially the same width as the cleaning pad(s).        -   On the other hand, some (or possibly all) of the polishing            pads may be arranged forwards of the cleaning pad(s). An            example of this is provided by the robot of FIGS. 2 to 4,            where one of the polishing pads 530A is located forwards of            the cleaning pad 520 (with the other polishing pad 530B            being located rearwards of the cleaning pad 520).

As in the robot shown in FIGS. 2 to 4, all the three above stages may beperformed in one path, where the agitator is at the front of the robotand the cleaning pad and polishing pads following it. As an alternative,a symmetric arrangement could be provided, with an agitator (or a numberof agitators) at the front and rear of the robot, with polishing andcleaning pads being located therebetween. Such an arrangement may, forexample, enable the “agitating” stage of cleaning to occur prior to the“wetting” stage, regardless of whether the robot moves forwards orbackwards over the window surface.

More generally, although the above cleaning strategy has beenillustrated using the robot of FIGS. 2 to 4, it should be appreciatedthat such a cleaning strategy may be implemented with a wide range ofrobot constructions, since it does not rely on a particular movement,navigation, attachment system etc. in order to be implemented.

The robot of FIGS. 2 to 4 is therefore viewed as being a specificexample of the much more general concept, whereby there is provided awindow-cleaning robot comprising: a movement system configured formoving the robot over a window surface and operable with a predefinedforwards direction of movement; at least one agitator configured forremoving debris from a window surface; at least one cleaning pad forremoving debris from the window surface, the at least one cleaning padarranged on the robot to follow the at least one agitator when themovement system moves the robot in the predefined forwards direction ofmovement; and wherein said at least one agitator and said at least onecleaning pad are arranged such that, as said movement system moves therobot over the window surface in said forwards direction, the at leastone agitator addresses a first width in a width direction, which isperpendicular to said forwards direction and parallel to the windowsurface, and at least one cleaning pad addresses a second width in saidwidth direction, said first width being substantially equal to orgreater than said second width.

The first width (that addressed by the agitator(s)) may, moreparticularly be a contiguous width. Hence, where there are a number ofagitators, there may, for example, be no gap, in the width direction,between the width addressed by any one of the agitators and theconsecutive agitator in the width direction. Similarly, the second width(that addressed by the cleaning pad(s)) may be a contiguous width.Hence, where there are a number of cleaning pads, there may, forexample, be no gap, in the width direction, between the width addressedby any one of the cleaning pads and the consecutive cleaning pad in thewidth direction.

Cleaning System with a Cleaning and a Polishing Pad

The following section of the disclosure also relates to the cleaningsystem of a robotic window cleaner.

Testing carried out by the Applicant indicates that a good finish isprovided when a robot has both one or more cleaning pads and one or morepolishing pads. The cleaning pad(s) are wetted with a cleaning fluid andcontact the window surface so as to remove debris therefrom with the aidof the cleaning solution. The polishing pad(s), polish the windowsurface when the robot is moved over it by thinning and/or dispersingthe layer of cleaning fluid left by the cleaning pad(s). It isconsidered that, as the human eye is very sensitive to differences, thismay improves the finish, making the window surface appear more “shiny”to the user.

The robot of FIGS. 2 to 4 is therefore viewed as being a specificexample of the much more general concept, whereby there is provided awindow-cleaning robot comprising: a movement system, configured to movethe robot over a window surface; one or more cleaning pads, configuredto be wetted with a cleaning fluid and to contact the window surface soas to remove debris therefrom with the aid of the cleaning solution; andone or more polishing pads configured to contact the window surface and,thereby, to polish it when the robot is moved over the window surfaceusing said movement system, each polishing pad polishing the windowsurface such that any layer of cleaning fluid present on the windowsurface is left as a thinner layer and/or is dispersed over a greaterarea after the polishing pad passes over it.

As discussed in the previous section, a reservoir containing cleaningfluid may be provided within the robot adjacent the cleaning pad. Thisreservoir may be fluidically connected so as to supply cleaning fluid tothe cleaning pad (rather than to the polishing pads; indeed, in someembodiments, the polishing pads will not be fluidically connected to anysource of fluid or reservoir). Alternatively, such a reservoir may befluidically connected so as to apply cleaning fluid directly to thewindow surface, for instance, at positions forwards of and adjacent tothe cleaning pad, so that the cleaning pad will be wetted by thecleaning fluid shortly after the cleaning fluid is applied to the windowsurface. As a further alternative, the user may themselves applycleaning fluid to the cleaning pad, for example by spraying the fluidonto the cleaning pad using a spray bottle.

Low-Power Attachment System

The following section of the disclosure relates to suction-basedattachment systems for window-cleaning robots.

With robots having such suction-based attachment systems, because theuser will not necessarily be near the robot when its battery runs low,it may be helpful to the user for the robot to be able to keep hangingon the window using its attachment system, perhaps for several hours,until the user is able to remove it.

It is therefore envisaged to provide a window-cleaning robot having anattachment system that includes both an active-mode sealing member (suchas the sealing foil 610 of the robot of FIGS. 2 to 4) and one or morepaused-mode sealing members (such as the suction cups 620A, 620B of therobot of FIGS. 2 to 4). Each of these sealing members seals a respectivespace between the robot and the window surface 1000.

In a similar manner to that described above, such a robot may beprogrammed (e.g. by suitable programming of its processor(s)) to operatein a “paused” mode, where the robot remains stationary on the surface ofthe window, and a number of “active” modes, where the robot moves overthe surface of window, using its movement system.

According to concept(s) disclosed in this section of the disclosure, inthe “paused” mode, the robot is programmed (e.g. by suitable programmingof its processor(s)) so that the vacuum pumps of its attachment systemreduce the air pressure within the spaces sealed by the paused-modesealing members to a sufficient extent to attach the robot to the windowsurface.

Conversely, according to concept(s) disclosed in this section of thedisclosure, in each of the “active” modes, the robot is programmed (e.g.by suitable programming of its processor(s)) so that the vacuum pumps ofits attachment system are caused to reduce the air pressure within thespaces sealed by the active-mode sealing member to a sufficient extentto attach the robot to the window surface, while permitting movement ofthe robot over the window surface.

By providing separate active-mode and paused-mode sealing members, eachtype of sealing member may be better configured for these functions(active-mode sealing members provide a seal that is sufficient to attachthe robot to the window surface, while permitting movement of the robotover the window surface, whereas paused-mode sealing members need onlyprovide a seal that is sufficient to attach the robot to the windowsurface). Accordingly, the paused-mode sealing members may be configuredto provide a tighter seal than the active-mode sealing members.

In addition, or instead, the paused-mode sealing members may be formedof material(s) that have a coefficient of friction with glass that isgreater than the coefficient of friction with glass of the material(s)from which the active-mode sealing members are formed. This may, forexample, assist the robot in “hanging” on the window surface during thepaused mode and in moving over the window surface during the activemodes.

The vacuum pumps of the attachment system may consume significantly lesspower in the “paused” mode than in the “active” modes. This might, forinstance, result from the paused-mode sealing members being configured(e.g. in terms of their shape and/or material) to provide a tightersealing than the active-mode sealing members and/or from more airleaking from the active-mode sealing members as a result of the movementduring the active modes, thus leading to an inherently less tight sealthan with the paused-mode sealing members.

The robot may include one or more pressure sensors (such as the pressuresensors provided within the holes 623A, 623B in the suction-cups 620A,620B of the robot 1 illustrated in FIGS. 2 to 4). Each of these pressuresensors may be arranged to sense the pressure within the space sealed bya corresponding one of the paused-mode sealing members. The robot may beprogrammed (e.g. by suitable programming of its processor(s)) so as tooperate the vacuum pumps in dependence upon the pressure within thepaused-mode sealing members, as measured by these pressure sensors.

In a specific example, the robot may be programmed (e.g. by suitableprogramming of its processor(s)) such that, during the paused mode, itcauses the vacuum pumps to reduce the pressure within the paused-modesealing members (as measured by these pressure sensors) to below a firstthreshold value. This threshold value may, for example, be sufficient toensure that the robot will typically remain attached to the window for asignificant period of time, such as in the region of tens of minutes, orperhaps several hours. Once this pressure has been achieved, the vacuumpumps are deactivated until the pressure within the paused-mode sealingmembers (again, as measured by the pressure sensors), rises above asecond threshold value (which will generally be greater than the firstthreshold value). This threshold level may be sufficient to ensure thatthe robot remains attached to the window surface for a significantperiod of time, albeit one that is typically shorter than the period oftime corresponding to the first threshold value, such as severalminutes.

In this way, the pressure reaching the first threshold value may beviewed as a warning that the robot may relatively soon detach from thewindow surface. Accordingly, once the pressure has reached (or indeedrisen above) this second threshold value, the robot may reactivate thevacuum pumps until the pressure is again reduced to (or below) the firstthreshold value. Generally, the time taken to return the pressure to thefirst threshold value from the second threshold value, using the vacuumpumps, will be far shorter than the time taken for the pressure toincrease from the first threshold value to the second threshold value,owing to leakage. Thus, the vacuum pumps will typically be active foronly a very small proportion of the time that the robot is in “paused”mode.

It will be understood that the vacuum pumps could operate at a lowlevel, rather than being deactivated, though it will be understood thatdeactivation may result in less power being consumed.

Each of the paused mode sealing members may be moveable between a firstposition, where it is spaced apart from the window surface, and a secondposition, where it contacts the window surface so as to seal a spacebetween the robot and the window surface. The robot may be programmed(e.g. by suitable programming of its processor(s)) such that, during theactive modes, the paused mode sealing members are moved to theirrespective first positions. As they do not contact the window surface inthese first positions, they will not be a source of friction as therobot moves over the window surface. In contrast, the active-modesealing members may remain in contact with the window surface whetherthe robot is operating in an active mode or in the paused mode and/orwhether the paused-mode sealing members are in their first or secondpositions.

The movement between these first and second positions may includedeformation of the paused-mode sealing members; for instance, the firstposition may correspond to each paused-mode sealing member being in anundeformed state and they may be moved into the second position bydeformation, instead of, or in addition to, translation.

It will be appreciated that, the greater the amount of frictionalresistance to movement that is experienced by the robot, the more forcethat is required to be produced by the movement system, thus generallyincreasing power consumption. In addition, the attachment system mayneed to provide a higher attachment force in order to enable themovement system to apply a greater force to the surface (e.g. using itswheels, tracks etc.) to move over the surface without slipping. Again,this generally increases power consumption.

Referring now to FIGS. 2 to 4, in this example of a window-cleaningrobot 1, the paused mode sealing members comprise respective suctioncups 620A, 620B, while the active-mode sealing member comprises asealing foil 610.

As noted further above, the suction cups 620A, 620B of this robot 1 mayprovide a low-power “parking” mechanism when the robot is operating in a“paused” mode. Thus, the suction cups 620A, 620B, together with theirassociated mounting and connections, of the robot 1 of FIGS. 2 to 4 maybe viewed as examples of paused-mode sealing members. As also notedfurther above, the suction cups 620A, 620B are normally at the chassissurface level, but may be moved towards the window surface 1000 underthe control of the processor(s) 101 of the control system 100, with avacuum then being created within the space sealed by each suction-cup620A, 620B using a vacuum pump 640. Thus, they are each moveable betweena first position, where they are spaced apart from the window surface1000, and a second position, where they contact the window surface 1000so as to seal a space between the robot 1 and the window surface.

Reference is now directed to FIGS. 8 to 10, which show in further detailthe suction cups 620A, 620B of the robot of FIGS. 2 to 4. FIG. 8A is aperspective view of one of the suction cups 620 of the robot of FIGS. 2to 4, together with its associated mounting 624, with the view beingtaken from the side opposite that which engages with the window surface.FIG. 8B, by contrast, is a perspective view of the suction cup 620 andassociated mounting of FIG. 8A, taken from the side that engages withthe window surface.

As may be seen from FIG. 8A, the suction cup mounting 624 includes twopipes 625, 626, one of which (pipe 625) connects with an internal space622 between the suction cup mounting 624 and the suction cup 620 itself.As will be discussed in further detail below, in order to move thesuction cup 620 into the second, window surface 1000 engaging position,a vacuum pump (typically a diaphragm-based vacuum pump) removes airthrough this pipe (pipe 625) so as to reduce the pressure within theinternal space 622. The other pipe (pipe 626) connects with the hole 623within the suction cup 620, so as to allow the pressure to be sensedwithin the space sealed by the suction cup 621 between the robot 1 andthe window surface 1000.

In more detail, once the suction cup 620 of FIGS. 8A and 8B is attachedto the window, a vacuum pump (typically a diaphragm-based vacuum pump)keeps removing the air between the suction cup 620 and the surface untila desired level of vacuum is obtained (e.g. the air pressure reaches thefirst threshold value discussed above). The pump then shuts-down untilthe air pressure, measured by a pressure sensor (connected through pipe626 to the vacuum pickup hole 623 within the space sealed 621 betweenthe robot 1 and the window), rises to above a threshold (e.g. the airpressure reaches the second threshold value discussed above). Thiscontrol cycle may reduce the amount of energy consumed by the vacuumpump (which may typically already be 10-20 times lower than the impellersystem, since the vacuum pump generates a substantially lower air-flow).The specific amount by which energy consumption is reduced may, forexample, depend on the sealing level between the suction cup 620 and thewindow surface, but the reduction could, for instance, be by a factor of10. Thus, in total, the vacuum pump for the suction cups 620 may consumeless than 1% of energy consumed by the impeller system. Accordingly, therobot of FIGS. 2 to 10 may be able to hang for long periods of time inthe paused mode, even when the battery level is low.

The robot of FIGS. 2 to 4 includes a mechanism to move the suction cupsto the window surface 1000, when attachment is desired (e.g. for thepaused mode), and away from the window surface 1000, when attachment isnot required (e.g. in the active modes). Moving the suction cups awayfrom the window when they are not required for attachment may reduce thefrictional forces experienced by the robot 1 when moving.

This mechanism is illustrated in FIG. 9 and FIGS. 10A-10C, in which FIG.9 shows a perspective view of a cross-section of one of the suction cups620 and its associated mounting, the cross-section being taken in aplane perpendicular to the surface of the window.

As is shown in FIG. 9, the suction cup 620 is provided with a valve627,628, 629, which in the specific example shown is a spring-suspendedvalve, which includes a valve body 627, secured to the suction cup 620,and a valve head 628 that is spring-loaded with spring 629.

Once the pump is activated, the air is initially vacuumed from theinternal space 622; this initial position is illustrated in FIG. 10A.Since the suction cup 620 is made of a soft material (typically silicon30 Shore), when the pressure in the internal space 622 drops, the cup620 is distorted in a way that turns it into a cone and moves it intocontact with the window surface 1000, as shown in FIG. 10B. Thus, eachsuction cup 620 is moved to a window-engaging position by deformation.As a result, the suction cup 620 seals a space 621, shown clearly inFIG. 10B, between the robot and the window surface 1000.

As illustrated by FIG. 10C, the vacuum in the internal space 622 keepsincreasing until the point at which the valve head 628 is attracted witha force greater than the force provided by spring 629. This correspondsto the difference between the pressure within the internal space 622 andthe pressure within the space sealed by the suction cup 620 beinggreater than a third threshold value.

The spring-suspended valve then opens, with the valve head 628 movingaway from the valve body 627, and the internal space 622 is as a resultconnected to the space 621 sealed between the robot 1 and the window,permitting the passage of air therebetween.

The vacuum in both spaces 621, 622 is now the same, and is lower thanthe vacuum which was previously applied to the space sealed with thewindow 621 but higher than the vacuum which was previously applied tothe internal space 622. Accordingly, the valve 627,628, 629 will closeand the space sealed with the window 621 will be isolated. This processcontinues and in due course stabilizes at a certain vacuum level withinthe space sealed with the window 621 that depends on the amount ofleakage from and the size of the space sealed with the window 621, aswell as the specific properties of the vacuum pump.

In the robot of FIGS. 2 to 4, two suction cups 620A, 620B are used inparallel in order to provide the required attachment force. This mayprovide more balanced torques, so that the robot is less likely torotate on the window surface 1000. However, in other examples only onesuction cup might be included, or more than two suction cups could beincluded.

In order to disengage the suction cups from the window surface 1000, theprocessor(s) of the control system 100 of robot 1 cause the attachmentsystem 600 to release the vacuum from the space sealed with the window621. This may be achieved, for example, by deactivating the vacuum pumpand waiting for the leakage to reduce the vacuum in the space sealedwith the window 621 (which may take some time) or by opening a manual orelectrical valve suitably connected to pipe 626 (in parallel to thepressure sensor).

In the robot of FIGS. 2 to 4, since the suction cups 620A, 620B arewithin the area sealed by the sealing foil 610, the pressure sensorsactually measure the vacuum in this area acted on by the impeller(s) 630when the suction cups 620A, 620B are disengaged from the window. In thisway, a single pressure sensor can be used in the control of both theimpeller attachment and the suction cup attachment. Thus, when the robot1 of FIGS. 2 to 4 operates in an active mode, the pressure sensor maymonitor the vacuum level within space sealed by the sealing foil 610(which might, in one example be around 20 mBar) and, when the robot 1 isswitched to a paused mode (for example in response to user actuation ofan operation mode control, or in response to the power system 200indicating to the processor(s) 101 of the control system 100 a lowbattery level), the vacuum pump 640 for the suction cups 620A, 620B maybe activated, with the suction cups 620A, 620B moving towards the windowsurface 1000.

Once the suction cups 620A, 620B contact the window surface 1000, andseal respective spaces 621 between the robot and the window surface1000, the vacuum in these spaces 621 will increase (in one example, toaround 400 mBar) to a desired level. Upon reaching this desired level,the impellers 630A, 630B can be stopped and the robot 1 should remainhanging on the suction cups 620A, 620B. However, if the vacuum level, asmeasured by the pressure sensors adjacent the suction cups, does notreach this desired level, which may indicate that the suction cups arenot making a sufficiently effective seal with the surface, the impellers630A, 630B will not turn off (though it might reduce speed andconsequently provide a lower vacuum level that conserves energy, butnonetheless maintains the attachment to the window surface 1000) andwarn the user that the hang time is short.

While in the robot of FIGS. 2 to 4 and the discussion above, the pausedmode sealing members comprise suction cups 620A, 620B, it should beappreciated that any suitable configuration might be used. For example,the paused mode sealing members might each include an element generallysimilar in shape and construction to the sealing foil 610. Inparticular, it will be appreciated that it is clearly not necessary forthe pause-mode sealing members to be moved into contact with the windowsurface 1000 by deformation: they might instead (or in addition)translated relative to the robot body, for example using a motor orother electrically powered arrangement.

Similarly, while the active-mode sealing member is described ascomprising a sealing foil 610, any suitable configuration might be used.Further, while only one active-mode sealing member is used in the robotof FIGS. 2 to 4, it will be appreciated that any suitable number ofactive-mode sealing members might be used.

Automatic Attachment to the Window Surface

The following section of the disclosure relates to the activation by theuser of the attachment system for a window-cleaning robot, such as thatshown in FIG. 1 or that shown in FIGS. 2 to 4.

In some products in the market, the user is required to turn thevacuuming on and then attach the robot to the window.

Use of Proximity Sensors

In contrast to such an approach, it is proposed that a window cleaningrobot may be provided with one or more proximity sensors, with the robotbeing configured (e.g. by suitable programming of the processor(s)) todetermine whether it is in close proximity to the window surface usingthese proximity sensors and with the robot being programmed (e.g. bysuitable programming of its processor(s)) such that the attachment forceis varied based on the proximity of the robot to the surface of thewindow, as determined by these proximity sensors. The use of such arobot is considered to be significantly more intuitive for the user.Additionally, or alternatively, such a robot may use less power, sincethe attachment system may operate in a low-power mode or be deactivatedcompletely when the robot determines, using the proximity sensors, thatit is not in close proximity to the window surface.

It should be appreciated that such a robot may be implemented using awide variety of attachment systems, not to mention a wide variety ofcleaning, power, movement and other systems.

Such proximity sensors may be configured to allow the robot (e.g. bysuitable programming of its processor(s)) to quantitatively determineits distance from the window surface or may simply be configured (e.g.by suitable programming of its processor(s)) to allow the robot to makean essentially binary determination as to whether the window surface iscloser to the robot than a specific distance.

Referring to the robot of FIGS. 2 to 4, purely by way of example, such astrategy may be implemented by activating the impeller only when theprocessor(s) of the robot determine, using the proximity sensors, thatthe window surface is in close proximity to the robot. Otherwise, theprocessor(s) of the control system may control the attachment systemsuch that the impeller rotates at a low speed, or is not moved at all;in either case, power is conserved, thus improving battery-life for therobot. The robot also makes less noise (the slower the impeller speedthe more quiet it typically is), which may be particularly beneficial inthe home or office environment.

Use of Orientation Sensors

It is further envisaged that, in addition or instead, a window cleaningrobot may be provided with one or more orientation sensors, with therobot being configured (e.g. by suitable programming of theprocessor(s)) to determine the direction in which it is oriented usingthese orientation sensor(s) and with the robot being programmed (e.g. bysuitable programming of its processor(s)) such that the attachment forceis varied based on the robot direction, as determined using theseorientation sensors. The use of such a robot is also considered to besignificantly more intuitive for the user than products currently in themarket. Additionally, or alternatively, such a robot may use less power,since the attachment system may operate in a low-power mode or bedeactivated completely, for example when the robot direction isdetermined to be at, or close to the horizontal.

For example, the robot may be provided with one or more orientationsensors, such as accelerometers or gyroscopes, with the robot beingconfigured to determine the direction in which it is oriented usingthese orientation sensor(s). The thus-detected robot orientation may beused to determine the level of the attachment force provided by theattachment system.

In more detail, in some examples, the attachment force may be determinedby the processor(s) of the robot based on the robot's orientation (asdetermined using the orientation sensor(s)) with respect to thehorizontal. In such examples, the robot's orientation may, for instance,be defined within the programming of the robot (e.g. within theprogramming of its processor(s)) as the angle between the plane of thewindow-engaging surface of the robot (e.g. the surface of the robot 1that is visible in FIG. 2) and the horizontal plane. More particularly,this angle may, for example, be defined as zero in the situation wherethe window-engaging surface is horizontal and faces verticallydownwards,

In still further detail, when the robot is disposed horizontally (suchas during charging, storage, or carrying) the processor(s) of thecontrol system may control the attachment system such that theattachment force is substantially lower than that typically required toattached the robot to the window surface or indeed such that it issubstantially equal to zero. For instance, where an impeller is used,this may correspond to the impeller rotating at a low speed, or notmoving at all.

By contrast, when the orientation sensor(s) indicate that the robot isdisposed at a 45 degree angle to the horizontal, the attachment systemmay be caused by the processor(s) to provide an attachment force at afirst level. For instance, where an impeller is used, this maycorrespond to the impeller being rotated at high speed so as to providesufficient attachment force to attach the robot to the window surfacewhen brought into contact with it. Further, when the robot is disposedvertically, or within, for example, 10 degrees of vertical (i.e. isdisposed at approximately 90 degrees to the horizontal), the attachmentsystem may be caused by the processor(s) to provide an attachment forceat a second level, which is significantly greater than the first level.For instance, where an impeller is used, this may correspond to theimpeller being rotated at a still higher speed so as to providesufficient attachment force to attach the robot to the (substantiallyvertical) window surface when brought into contact with it.

Furthermore, if the window is horizontal, but the robot is oriented soas attach to to its underside (corresponding to the robot'swindow-engaging surface being oriented at 180 degrees with respect tothe horizontal), it may need a particularly high attachment force.

In robots with both proximity and orientation sensors, the attachmentforce may be varied based on both the robot orientation, as determinedusing the orientation sensors, and whether the robot is in closeproximity to the surface of the window, as determined using theproximity sensors.

The robot may thus be programmed (e.g. by suitable programming of itsprocessor(s)) such that when it determines that it is close proximity tothe surface of the window using the proximity sensors and itsorientation is within a predetermined angular range with respect to thehorizontal (for example its window-engaging surface is oriented at anangle greater than 20 degrees to the horizontal), the attachment forceis increased to at least a threshold value. This may be a level that issufficient to ensure the robot has generally sufficient traction to movearound on a window at a relatively small angle with respect to thehorizontal. For instance, this may be the attachment force necessary forthe robot to move on a window disposed at an angle that is slightlygreater than the lower end of the predetermined angular range (e.g. 25degrees in the example given above), for example so as to allow forminor errors in determination of the robot's orientation). Equally, thisthreshold value could simply be zero, though such an arrangement may beless robust.

Suitably, the processor(s) of the robot may determine an attachmentforce that exceeds this threshold value level by an amount based on therobot orientation, as determined using the orientation sensors. Thus,where the window is vertical, or where the robot is attached to thebottom surface of a window, a suitably high attachment force may beprovided by the attachment system. This may further reduce power usageby the robot, since an appropriate level of force may be applied, giventhe orientation of the window.

The amount by which the threshold value is exceeded may be determinedusing a formula programmed into the processor(s) of the robot, or usinga lookup table with a series of values for the attachment forcecorresponding to respective angular bands within the predeterminedangular range (e.g. an attachment force value for 20-40 degrees, a valuefor 41-60 degrees, a value for 61-80 degrees, and so on).

Conversely, the robot may be programmed (e.g. by suitable programming ofits processor(s)) such that, when it determines that its orientation iswithin a predetermined angular range of the horizontal (e.g. within 20degrees of the horizontal), the attachment force is set to a level thatis equal to or less than a second, lower threshold value, typically zeroor a small stand-by value. Similarly, the robot may be programmed (e.g.by suitable programming of its processor(s)) such that, when itdetermines that it is not in close proximity to the surface of thewindow (with the aid of the proximity sensor(s)), the attachment forceis set to a level that is equal to or less than the same secondthreshold value.

Use of Pressure Sensors

In robots, such as that shown in FIGS. 2 to 4, where a suction-basedattachment system is utilised, the robot may be provided with a pressuresensor configured to measure a pressure in the attachment system (forexample in the space sealed between the robot and the window surface inwhich a vacuum is generated, e.g. the space sealed by sealing foil 610)and such a robot may be programmed (e.g. by suitable programming of itsprocessor(s)) to vary the attachment force based on the pressuremeasured by this pressure sensor. In a specific example, when thepressure measured by these pressure sensor drops below a predeterminedpressure, for example a predetermined amount below the pressure withinthe room (local atmospheric pressure), thus suggesting that the robothas been brought into contact with the window surface and has thusformed a partial seal, the robot is programmed (e.g. by suitableprogramming of its processor(s)) to increase the attachment force. Forinstance, the attachment force may be increased to above a thresholdvalue (such as the threshold values discussed above corresponding to ahorizontal window, or a window at a shallow angle). Further, where therobot is provided with orientation sensor(s) the attachment force mightbe increased to a level that is greater than a particular thresholdvalue by an amount determined in accordance with the robot orientationwith respect to the horizontal, as described in the precedingsubsection.

Suitably, the same pressure sensor that is used to determine when therobot is in contact with the window, by detecting the corresponding dropin air pressure, may additionally be utilised to sense local atmosphericpressure, for example as part of a start-up mode. Alternatively, anadditional pressure sensor might be provided to sense local atmosphericpressure; for example, such a sensor could be provided in or on the sideof the robot opposite to that which contacts the window surface).

Where proximity sensors are provided, the robot may be programmed (e.g.by suitable programming of its processor(s)) such that, when theproximity sensors indicate that the robot is in close proximity to thewindow surface, but the pressure sensor indicates that the pressure hasnot dropped substantially below the local atmospheric pressure, theattachment force is set at a second, lower threshold value. While lower,this second threshold value for the force may nonetheless be sufficientin order that, when the robot does contact the window surface, it causesthe pressure within the attachment system to drop significantly enoughto enable reliable sensing of this drop in pressure by the pressuresensor. Then, in response to this sensed drop in pressure, the robot maycause the attachment system to increase the attachment force to abovethe first threshold value, thus attaching the robot to the window.

In a simpler arrangement, the robot may be programmed (e.g. by suitableprogramming of its processor(s)) such that, the attachment force ismaintained at a low level until the proximity sensors indicate that therobot is in close proximity to the window surface and the pressuresensor indicates that the pressure has dropped substantially below thelocal atmospheric pressure, at which point the attachment force isincreased to above a threshold value, for example the first thresholdvalue described above.

It is envisaged that a robots which vary their attachment force based onthe pressure measured by pressure sensors in the manner described aboveneed not include orientation or proximity sensors, as described above.Such robots might simply rely on such pressure sensors to determine whenthey are in contact with the window and, in response, increase theattachment force from a low level, which conserves power, to a highlevel, which is sufficient to attach the robot to windows at most, orsubstantially all orientations.

However, where orientation sensors are provided, the robot mayadditionally, or alternatively, determine an attachment force thatexceeds the first threshold value level by an amount based on the robotdirection, as determined using the orientation sensors. As noted above,this may further reduce power usage, since an appropriate level of forceis applied, given the orientation of the window.

Use of Navigation Sensors

The attachment force can also (or instead) be controlled based on thedetected movement of the robot, determined using navigation sensorsprovided by the robot. The robot may be programmed (e.g. by suitableprogramming of its processor(s)) to detect unwanted motion using thesenavigation sensors.

Such navigation sensors might include sensors operable to sense therelative motion of the robot, such as accelerometers, odometers,gyroscopes or magnetometers. In a specific example, one or more of thenavigation sensors might detect rotation of an undriven wheel, such asthe castor wheels of the robot of FIGS. 2 to 4. Such navigation sensorsmight also, or instead include proximity sensors (e.g.front/rear-looking proximity sensors) that enable the robot to determineits distance from the window frame.

Such navigation sensors may be used, for instance, to enable the robotto detect departure from a planned path, in the case where the robot ismoving over the window surface, or movement, in the case where the robotis intended to be stationary. In a specific example, the robot maydetect when the robot slips on the window surface and, in response, mayincrease the attachment force until such slippage stops.

Control of Attachment Force

It should be understood that where, in the description above, referenceis made to the robot (and, more particularly its processor(s)) beingprogrammed to cause the attachment system to generate an attachmentforce having a particular level that this is the force that will beprovided in nominal conditions, for example the force that will beprovided when the robot is engaged with the window (in the case of avacuum/suction-based attachment system this is the attachment force thatwill be provided when the robot and any sealing members are actuallyengaged with the window surface). Therefore, in many cases, each valuefor the nominal attachment force may correspond to a respective powerlevel at which the attachment system operates.

Moveably-Mounted Cleaning Pad

The following section of the disclosure relates to the mounting of thecleaning pad on the robot body.

As briefly mentioned above, in the robot of FIGS. 2 to 4, the cleaningpad (and the polishing pads) are provided as part of a cleaning padmember that is separate from and moveably mounted with respect to themain body of the robot. The nature of this mounting and principlesembodied therein will now be described in further detail with referenceto FIGS. 11 to 14.

Turning first to FIGS. 11 and 12, which are, respectively: a is a viewfrom below of the cleaning pad member and the robot of FIGS. 2 to 4; anda perspective view of the rear section of the robot of FIGS. 2 to 4; andillustrates the specific arrangement used to mount this cleaning padmember to the main body of the robot; as is indicated by a double-endedarrow, the cleaning pad member 550 is moveably mounted on the main body10 of the robot 1 such that movement is restricted to the widthdirection W of the robot (which is perpendicular to the forwardsdirection F of the robot). Further, the cleaning pad member 550 (and thecleaning pad itself) is elongate in the width direction W.

The movement of the cleaning pad member 550 (and thus of the cleaningpad 520) with respect to the main body 10 is thus restricted to thelength direction of the cleaning pad 520 and of the cleaning pad member550.

It should be noted however that in other examples, the movement of thecleaning pad member may not be restricted in this manner. For instance,the cleaning pad member might be mounted such that it is free to movewith respect to the main body along an arc-shaped path.

Attention is now directed to FIGS. 13A-13C, which show further detailsof the arrangement by which the cleaning pad member 550 is mounted onthe main body 10 of the robot 1 shown in FIGS. 2 to 4.

Turning first to FIG. 13A, which is a perspective view of the cleaningpad member 550 and robot chassis 13 with various components removed toillustrate the mounting arrangement for the cleaning pad member, shownare rails 553A, 553B provided on the upper side (that opposite to theside providing the cleaning pad 520) of the cleaning pad member 550 andcorresponding rails 51A, 51B provided on the cleaning pad mount 50 ofthe main body 10. This cleaning pad mount 50 is shown in FIG. 13C, whichis a perspective view of a cross-section through the cleaning pad memberand this cleaning pad mount 50. As is apparent from FIGS. 13A-13C, therails 553A, 553B provided on the cleaning pad member 550 engage with therails provided on the main body 10, thus restricting movement of thecleaning pad member 50 to the width direction W of the robot 1.

Further shown in FIG. 13A is a spring 52, which is attached at one endto the cleaning pad member 550 and at the other end to the cleaning padmount 50 of the main body 10. This spring 52 mechanically biases thecleaning pad member 550 (and therefore the cleaning pad 520 also)towards a central position with respect to the main body 10, in whichthe cleaning pad member is aligned with the main body 10 along theforwards direction F. Accordingly, the cleaning pad member 550 willresist moving away from this central position, for example where a forceis applied to it by the window frame. It will of course be understoodthat other mechanical arrangements may provide such biasing to a centralposition and this is merely an illustrative example.

Turning next to FIG. 13B, which is a perspective view of a cross-sectionthrough the cleaning pad member, it is apparent that the cleaning padmember 550 also includes a support 552, to which the cleaning pad 520 isremovably attached, for example using Velcro, a magnetic or a mechanicalconnection; the cleaning pad may be removed and replaced, for examplewhen the cleaning pad 520 becomes worn from repeated use. This support552 is in turn mounted on the cleaning pad member housing 555. Morespecifically, it may be mounted on the cleaning pad member housing 555using a leaf spring 551, as is shown in FIG. 13B. In this way, thecleaning pad 520 may be pressed against the window surface 1000, forexample with a substantially constant force, so as to more effectivelyclean it. It will of course be understood that other mechanicalarrangements may provide such pressing of the cleaning pad against thewindow surface 1000 and that this is merely an illustrative example. Forinstance, the cleaning pad member 550 could be mounted on the rearportion of the main body 10 using a spring.

It should be noted that the cleaning pad member 550 may be configuredsuch that the polishing pads 530A, 530B are also pressed against thewindow surface 1000 and, moreover, are pressed against the windowsurface 1000 with greater force. In the example shown in FIG. 13B, theleaf spring 551 is configured to apply greater pressure to the sides ofthe support, where the polishing pads 530A, 530B are located, than tothe center of the support, where the cleaning pad 520 is located.However, it should be understood that this is merely an example of anarrangement by which polishing pad(s) are pressed against the windowsurface 1000 with greater force than cleaning pad(s) and otherarrangements may be utilized, particularly where the polishing pad(s)and cleaning pad(s) are positioned differently.

Attention is now directed to FIG. 14A, which is a plan view of the robot1 of FIGS. 2 to 4 carrying out a turn starting at an initial positionadjacent the frame of the window. As is apparent from FIG. 14A, in therobot's initial position, the cleaning pad member 550 has been forcedaway from its central position (towards which it is biased) by thewindow frame.

As may be seen from FIGS. 14B(i)-14B(iv), which are plan views of therobot 1 at respective points in the turn, as the robot 1 carries outthis turn, the side of the cleaning pad member 550 remains in contactwith the window frame for much of the turn. The window frame 1010 thuspushes the cleaning pad member 550 still further away from its centralposition, with the cleaning pad member 550 moving on the rails asdiscussed above. As a result, the robot 1 is able to turn in a positionwhere it would not be able to if the cleaning pad member 520 were fixedon the main body 10 of the robot 1. More generally, the robot 1 is ableto approach closer to the window frame than, for instance, if thecleaning pad member 550 were fixedly mounted on the main body 10 of therobot 1. This may assist the robot 1 in cleaning the window surface 1000all the way to its edge. Indeed, the robot 1 may, for example, be ableto clean the window surface 1000 to its edge without the robot main body10 touching the frame.

It may also (or instead) assist the robot in turning near corners of thewindow. For example, the robot may be programmed (e.g. by suitableprogramming of its processor(s)) so as to cause the robot to move in aforwards direction over the window surface 1000 alongside a window edge(for example as part of a “perimeter movement pattern” as discussedbelow) and, when it determines that it has reached a corner, to movepast the corner and so that it is alongside the consecutive window edgeand then to reverse into the corner, so that the cleaning pad 520 (whichmay be provided at the rearwards end of the robot) addresses the area ofthe window immediately adjacent the corner. Such a maneuver may be moreeasily carried out with the cleaning pad movably mounted with respect tothe main body of the robot.

Additionally, or alternatively, such a mounting arrangement may resultin reducing the amount of time the main body 10 comes into contact withthe window frame (in some cases only the cleaning pad member 550 maycontact the window frame), which may comparatively reduce the frictionalforces on the robot, which might otherwise affect control of the robot.

As is also apparent from FIGS. 14A and 14B, the robot is furtherassisted in approaching closer to the window frame as a result of themain body 10 having a profile (when viewed from the side that contactsthe window surface 1000) that is narrower at the end on which thecleaning pad member 550 is mounted. The curved profile of this end(which is the rearwards end of the robot of FIGS. 2 to 4) still furtherassists in allowing the robot 1 to approach close to the window frame.

A further example of the cleaning pad member 550 moving with respect tothe main body 10 and thereby allowing the robot 1 to approach closer tothe window frame is where the robot 1 is moving in a forwards direction,parallel to the window frame. For example, where the robot of FIGS. 2 to4 moves along such a path, the side of the cleaning pad member 550 maycontact the window frame, with the window frame pushing the cleaning padmember 550 away from its central position, along the rails 51A, 51B onwhich it is mounted. Particularly where the extent of the cleaning padmember 550 in the width direction W (which is perpendicular to theforwards direction of the robot), is greater than the correspondingextent of the main body 10 of the robot in the width direction W, it maybe possible to avoid the main body 10 contacting the window frame (thusreducing frictional forces on the robot) while still allowing the windowsurface 1000 to be cleaned right up to its edge. The cleaning pad member550 might therefore be the widest point of the robot in the widthdirection W of the robot.

While a specific illustrative example of a mounting arrangement for thecleaning pad member 550 has been discussed above with reference to FIGS.11-14, it is envisaged that a wide range of mounting arrangements mightsimilarly enable the cleaning pad member 550 to move with respect to themain body of a robot, thereby allowing the robot to approach closer to awindow frame. For instance, the cleaning pad might be secured on acleaning pad member having one or more arms, each of which is pivotallymounted on the main body of the robot. It will be appreciated that, insuch a case, the movement of the cleaning pad member may not berestricted to (translation in) a single direction; for instance, themovement of the cleaning pad member may be restricted to an arc-shapedpath.

It should further be appreciated that the cleaning pad member need notinclude a housing, as is the case in the example above (although thismay assist in protecting the cleaning pad, for example from accidentaldamage by the user). For instance, a support, to which the cleaning padis removably attached (such as that described above), might be moveablymounted directly on the main body, rather than via the housing, asdescribed above.

While in the specific examples discussed above with reference to FIGS.2-4 and 11-14 the cleaning pad member comprises only one cleaning pad,it should be understood that the cleaning pad member may include anumber of cleaning pads.

Further, whether there is provided one cleaning pad or a number ofcleaning pads, the cleaning pad(s) may be arranged such that theyaddress a contiguous width in the width direction as the robot movesover the window surface in the forwards direction, with this contiguouswidth being substantially equal to or greater than the width of the mainbody in the width direction. As discussed in previous sections, thecleaning pad member may further comprise one or more polishing pads.These may address a contiguous width in the width direction that issubstantially equal to the width addressed by the one or more cleaningpads.

The robot of FIGS. 2 to 4 (with the mounting arrangement of FIGS. 11 to14) is therefore viewed as being a specific example of the much moregeneral concept, whereby there is provided a window-cleaning robotcomprising: a main body; a movement system, mounted on said main bodyand configured to move the robot over the surface of a window; acleaning pad member, which comprises one or more cleaning pads, eachcleaning pad being configured to be wetted with a cleaning fluid and tocontact the window surface so as to remove debris therefrom with the aidof the cleaning solution; wherein the cleaning pad member is moveablymounted on the main body such that when the cleaning pad member contactsa frame for the window, the frame pushes the cleaning pad member,causing the cleaning pad member to move with respect to the body therebyallowing at least a portion of the main body to approach closer to saidwindow frame than if the cleaning pad member were fixedly mounted on themain body.

Navigation by a Window-Cleaning Robot

The following section of the disclosure relates to navigation by awindow-cleaning robot (such as that detailed above with reference toFIGS. 2 to 4) when moving over a window surface using its movementsystem.

As briefly discussed above, a window cleaning robot may include anavigation system 300 having a variety of navigation sensors that assistthe robot in navigating around the surface of the window, when movingusing the movement system 400.

It is considered that a window cleaning robot with at least oneorientation sensor, with the robot being configured to determine itsorientation using such orientation sensors, and at least one distancesensor configured to detect the distance between the robot and the frameof the window, may be particularly effective at navigating around awindow surface.

Such distance sensors may, for example, be time-of-flight based sensorsand may thus make use of reflected infra-red, light, ultrasound and thelike. A particular example of a suitable time-of-flight sensor is theVL6180 optical time-of-flight sensor, supplied by ST Microsystems. Thedistance sensors may be directed generally in the forwards direction ofthe robot's movement system, as is the case with the robot shown inFIGS. 2 to 4.

The orientation sensors may, for example, be accelerometers orgyroscopes. The orientation sensors may enable the robot to determineits current orientation, for instance with respect to gravity or apredetermined orientation.

The effectiveness of such a robot in navigating around a window surface1000 will be explained with the aid of FIGS. 15 to 19. Each of thesefigures illustrates the robot using the measurements provided by itsorientation sensor(s) and distance sensor(s) to move along a path overthe window surface 1000. The path may be determined by the robot inaccordance with certain rules or policies that it has been programmedwith (e.g. that have been programmed into its processor(s)).

FIG. 15 illustrates a robot, which comprises the navigation sensorsdiscussed above, moving over the surface of a window having a framesurrounding its entire edge. The robot's location at a series of pointsin time is shown in FIG. 15, with the numbers (1)-(5) indicating theorder in which the robot arrives at such locations.

The robot of FIG. 15 is programmed (e.g. by suitable programming of itsprocessor(s)) such that it travels over a path including a plurality ofparallel segments, each of which extends from a position adjacent oneedge of the window to a position adjacent the opposite edge of thewindow surface 1000. Indeed, each of the parallel segments may extendacross substantially the whole of the window surface 1000. As isapparent, at locations (2) and (4) in FIG. 15 the robot is moving alongsuch parallel segments.

The robot is able to use its orientation sensor to ensure that each ofthese segments is parallel. In the example of FIG. 15, each of theparallel segments is vertical. Thus, the robot travels up and down,keeping an accurate direction by closing a control loop over theorientation sensors.

In addition, the robot is programmed (e.g. by suitable programming ofits processor(s)) such that, when the distance sensors indicate that therobot is a predetermined distance from the window frame, they cause therobot to begin moving along a turning segment of the path. Thus it mayperform a generally smooth turn or curved movement that brings it to theconsecutive parallel segment within the path. As is apparent, atlocations (3) and (5), the robot is moving along such smooth turns.

The path may be defined in the robot's programming (for example byselection of appropriate values for the radius of the turning segment)such that consecutive parallel segments are spaced apart by an amountthat is sufficiently small to ensure that the respective areas (orswathes) addressed by the robot's cleaning system on consecutiveparallel path segments may touch, or even overlap. Such an overlapmight, for example, be sufficient to take account of the accuracy of therobot's navigation system. For instance, the spacing might be defined asw−2e, where w is the active width of the cleaning system and e is theaccuracy of the navigation system.

Hence, or otherwise, as the robot moves along the path shown in FIG. 15,which is made up of parallel segments linked together by smooth turns,it will progressively apply its cleaning system to substantially theentire window surface 1000, with the exception of a perimeter portion1001 of the window surface adjacent the edge of the window. In this way,this central portion 1002 of the window surface can be cleaned in asingle, continuous forward movement by the robot. Hence, cleaning may befast and efficient. In addition, smooth turns may reduce the incidenceof marks being left on the window surface 1000 by the robot and/or mayreduce wear on the robot's movement system.

Moreover, in such a pattern the wheels will typically avoid travellingover an area the cleaning system has recently been applied to. Byavoiding such areas, which might be wet with cleaning fluid, incidencesof slippage may be reduced.

FIG. 16 illustrates a further example of a path including a plurality ofparallel segments. As with FIG. 15, the robot's location at a series ofpoints in time is shown in FIG. 16, with the numbers (1)-(4) indicatingthe order in which the robot arrives at such locations.

As is apparent, in contrast to the path followed in FIG. 15, the pathillustrated in FIG. 16 is defined in the robot's programming (e.g. theprogramming of its processor(s)) such that consecutive parallel segmentsare linked together by a short segment that is perpendicular to them.Thus, when the distance sensors indicate that the robot is apredetermined distance from the window frame, the processor(s) cause therobot to carry out a sharp turn (for example turning in place) and thento move in a perpendicular direction for a predetermined distance beforeagain carrying out a sharp turn and then continuing along theconsecutive parallel path segment.

Hence, as the robot moves along the path shown in FIG. 16, it willprogressively apply its cleaning system to the central portion 1002 ofthe window surface (substantially the entire window surface, with theexception of a perimeter portion 1001 of the window surface adjacent theedge of the window). Thus, again, the central portion 1002 of the windowsurface can be cleaned in a single, continuous forward movement by therobot, enabling fast and efficient cleaning of the window. Further, aswith the pattern of FIG. 15, in the pattern of 16 the wheels willtypically avoid travelling over an area the cleaning system has recentlybeen applied to, thus reducing incidences of slippage.

FIG. 17 illustrates the behavior of a robot moving over a window thathas a frame that extends around only a portion of the window's edge. Asbefore, the robot's location at a series of points in time is shown,with the numbers (1)-(7) indicating the order in which the robot arrivesat such locations. The navigation system of the robot in this example isadditionally provided with at least one window presence sensor, which isconfigured to detect the presence of the window adjacent a portion ofthe robot. Such a window presence sensor may be a proximity sensor andmay, for example, be provided on the side of the robot that engages withthe window surface 1000, or may otherwise be directed towards the windowsurface 1000. More particularly, the window presence sensors may beprovided towards the forwards end of the robot (as defined by themovement system), as is the case with the proximity sensors 320A, 320B,320C of the robot 1 of FIGS. 2 to 4.

The robot illustrated in FIG. 17 is programmed (e.g. by suitableprogramming of its processor(s)) to follow a path that is defined in itsprogramming in a similar manner to the path followed by the robot ofFIG. 15. However, the robot illustrated in FIG. 17 is additionallyprogrammed so as to react to gaps in the window frame. Specifically,because the frame does not extend around the whole of the window, themeasurement from the distance sensor(s) may be erroneous, for examplewhen the robot is driving directly towards a gap in the window frame. Asa result, the robot may continue to the edge of the window (as hashappened with the robot at location (2) in FIG. 17), since its distancesensors may not indicate that it has approached to within apredetermined distance of the window frame, which would normally triggerit to begin a turning movement. However, the robot is programmed (e.g.by suitable programming of its processor(s)) such that, as it approachesthe edge of the window, it responds to the window presence sensor(s)indicating that the window is not adjacent the robot by causing therobot to carry out a rearwards movement away from the window edge, forexample for a predetermined distance. In FIG. 17, the arrow shown inoutline indicates such a rearwards movement from location (2), where therobot is at the edge of the window, to location (3).

Having carried out this rearwards moment, the robot may then perform asmooth turn, as described above with reference to FIG. 15, andthereafter continue with the next parallel path segment.

Such a strategy may enable the robot to cover the central portion of thewindow surface 1002 in a substantially continuous movement, even wherethe surface is frameless at one or more of its sections.

As a still further refinement, the robot may keep track of the length ofeach of the parallel path segments. For example, it could store eachlength and determine the average, maximum and/or minimum lengths forthese segments; thus it measures a distance L corresponding to one ormore of the parallel path segments. This may be used as a safety measurein addition to, or instead of the window presence sensor.

Specifically, the robot may begin turning when it has travelled adistance I since its previous turn, where I may be greater than thecharacteristic length L for previous path segments by a small amount (ormight be equal to L). Thus, the robot will generally turn before itreaches the edge of the window, thus enabling it to cover the centralportion of the window in a substantially continuous movement. The numberof rearwards movements it needs to carry out may be reduced.

To assist the robot with determining the lengths of the parallel pathsegments, one or more relative motion sensors (e.g. an odometer, anaccelerometer, a gyroscope etc.) may be provided, for example as part ofthe navigation system. Of course, a distance sensor might equally beused to determine the lengths of the parallel path segments.

It will of course be appreciated that while in the examples of FIGS. 15to 17, the robot scans the window in a vertical direction (the parallelpath segments are oriented vertically), scanning may be horizontalinstead, as illustrated in FIG. 18. Testing carried out by the Applicantindicates that scanning paths where the parallel segments are orientedhorizontally may provide a particularly good finish to the windowsurface. This is thought to be because residual cleaning fluid fromprevious parallel segments, will tend, owing to gravity, to flowvertically downwards, and thus will be addressed in a generallycontinuous manner by subsequent parallel segments. In contrast, withvertically oriented parallel segments, such residual cleaning fluid maybe addressed in a more discontinuous manner.

For similar reasons, it is considered that a scanning path that startsadjacent the top of the window and finishes adjacent the bottom of thewindow may provide a particularly good finish to the window surface.

More generally, the parallel paths could be oriented in any direction;however, as the edges of windows generally extend either horizontally orvertically, it may be simpler to program the robot so as to use either ahorizontal or a vertical scanning direction.

As will be appreciated, FIGS. 15 to 18 illustrate the robot moving alonga path that is defined such that the robot covers a central portion 1002of the window surface 1000. Thus, the paths shown in FIGS. 15 to 18 maybe considered as respective examples of “interior movement patterns”.

In order to ensure complete coverage of the window, the processor(s) ofthe robot may be additionally programmed to cause the robot to carry outa “perimeter movement pattern”, where the robot performs a circuit ofthe window, where it moves adjacent to the edge of the window, so as tocover a perimeter portion 1001 of the window surface 1000. An example ofsuch a perimeter movement pattern is shown in FIG. 19. Suitably, thecentral portion cleaned when the robot carries out the interior movementpattern may be sufficiently large that the perimeter portion that mustbe cleaned extends a distance less than the width of the robot from theedge of the window. Thus, the perimeter portion may be covered in asingle circuit of the window. This is, of course, not essential: as partof the perimeter movement pattern, the robot might carry out a number ofcircuits so as to cover the window surface 1000, with each circuit beingoffset from the previous circuit.

For such a perimeter movement pattern, it may be helpful for the robotto be able to get the agitator and/or the cleaning pad as close aspossible to the edge of the window. For the agitator, this can be doneby some angled bristles that can reach outside the agitator housing, oralternatively by an additional side-mounted agitator, such as a sidebrush.

As discussed further above with reference to FIG. 1 and the robotdetailed above with reference to FIGS. 2 to 4, it is envisaged thatwindow cleaning robots as described herein may operate in a number ofoperation modes. One such operation mode may be a “full cleaning” mode,where the robot is configured to clean substantially the entire surfaceof the window (such a “full cleaning” mode may characterised as an“active” mode as described herein, since the robot moves over thesurface of window, so as to clean it). In such a “full cleaning” mode,the robot may first move over the window surface 1000 according to aninterior movement pattern, such as one of the scanning strategiesdescribed above with reference to FIGS. 15-18, to clean the centralportion of the window surface and then to move over the window surface1000 according to a perimeter movement pattern, carrying out a circuitof the window adjacent the window edge (for example according to theedge cleaning strategy discussed above with reference to FIG. 19), so asto clean the perimeter portion of the window. Of course, it will beappreciated that the perimeter portion could be cleaned prior to, ratherthan after, the central portion.

It should be appreciated that it is not essential that a robot with atleast one orientation sensor, with the robot being configured todetermine its orientation using such orientation sensors, and at leastone distance sensor configured to detect the distance between the robotand the frame of the window, moves along a path including a number ofparallel segments. The robot could move along a path that is partiallyrandom; for example a path including a number of generally straight pathsegments, each of which has an orientation that is determined at leastpartially randomly.

In a specific example, the robot might move along a generally straightpath segment until its distance sensor indicates that it is apredetermined distance from the boundary. In response, it may carry outa generally smooth turn, as described above with reference to FIGS. 15,17, and 18, and then move along a further, generally straight pathsegment. However, in contrast to the approaches discussed above withreference to FIGS. 15-18, this further, generally straight path may bedisposed at an angle to the previous generally straight path segmentthat is determined at least partially randomly. For example, the robotmay determine an angle according to a suitable random function andcontinue moving along the generally smooth turn until determines, usingits orientation sensors, that it is at that randomly-determined angle,whereupon it will travel upon a generally straight path segment, untilit encounters the window edge again.

Thus, according to such a strategy, the robot might be described as“bouncing” off the edges of the window. Over time, the robot may beexpected to cover the entire window surface using such a strategy.Hence, the robot might be programmed (e.g. by suitable programming ofits processor(s)) to operate for longer than a specific period of timethat is sufficient to provide a high level of certainty that the robothas covered the entire window surface. This period of time could, forexample be determined based on the measured lengths of the generallystraight path segments; thus, where longer lengths are measured,indicating a larger window, the robot would operate for acorrespondingly longer period of time.

It should accordingly be appreciated that the strategies described abovewith reference to FIGS. 15-19 are merely specific examples of a windowcleaning robot a movement system, configured to move the robot over thesurface of a window and, thereby, to enable the robot to clean thewindow surface; at least one orientation sensor, the robot beingconfigured to determine its orientation using the at least oneorientation sensor; at least one distance sensor configured to detectthe distance between the robot and the frame of the window; wherein therobot is programmed (e.g. by suitable programming of its processor(s))to move, using the movement system, over the window surface, navigatingbased on measurements provided by the orientation sensor(s) and thedistance sensor(s).

Separate Perimeter and Interior Coverage

The following section relates to strategies by which the robot movesover the window surface to clean the window and, in particular,strategies by which the robot cleans substantially all of the windowsurface.

Testing carried out by the Applicant has led to the realization thatensuring good coverage of the area at the edge of the window surface isparticularly difficult, since the movement of the robot in this area—andtherefore the application of its cleaning system to the windowsurface—may be impeded by the window frame. Further, errors in coverageadjacent the window frame will often result in generally linear areasbeing left unaddressed by the cleaning system. As the human eye isparticularly adept at identifying linear features, such errors incoverage are especially noticeable to the user.

Furthermore, it is considered that a perimeter movement pattern such asthat illustrated in FIG. 19) where the robot carries out at least onecircuit of the perimeter of the window surface 1000, thus cleaning astrip 1001 of the window surface 1000 that extends around the perimeterof the window surface and is bounded by the edge of the window surface,may allow the area at the edge of the window surface 1000 to becarefully and simply addressed by the cleaning system. The remainder ofthe window surface 1002, where the frame is unlikely to impede movementof the robot, may then be addressed separately, by carrying out asuitable interior movement pattern, for example where the robot followsa scanning path, such as one of those shown in FIGS. 15-18.

It is accordingly considered that efficient and reliable coverage of theentire window surface may be provided by programming the robot (e.g. byprogramming its processor(s)) to separately carry out an interiormovement pattern (such as one of those illustrated in FIGS. 15-18) and aperimeter movement pattern (such as that illustrated in FIG. 19), wherethe perimeter movement pattern is defined in the robot's programmingsuch that the robot carries out at least one circuit of the perimeter ofthe window surface, thus cleaning a strip 1001 of the window surface1000 that extends around the perimeter of the window surface 1000 and isbounded by the edge of the window surface, and where the interiormovement pattern is defined in the robot's programming such that therobot cleans the area 1002 located within the strip 1001 of the windowsurface 1000 cleaned during the perimeter movement pattern.

Such a strategy may be more fully understood with the aid of FIG. 20,which illustrates the strip 1001 of the window surface 1000 cleaned bythe robot when carrying out the perimeter movement pattern illustratedin FIG. 19. As is apparent, this perimeter strip has a width W_(P),which may be substantially equal to the width of the robot. As is alsoshown, an area 1002, around which strip 1001 extends, is not addressedas part of the perimeter movement pattern. As noted above, this interiorarea 1002 may be addressed by the robot carrying out an interiormovement pattern, such as one of those illustrated in in FIGS. 15-18. Tofurther ensure complete coverage of the window surface 1000, theinterior movement pattern may be defined in the robot's programming(e.g. the programming of its processor(s)) such that the area that therobot cleans overlaps with the strip 1001 of area that is cleaned as aresult of the perimeter movement pattern.

Such an overlap might, for example, be sufficient to take account of theaccuracy of the robot's navigation system. For instance, the spacingmight be defined as w−2e, where w is the active width of the cleaningsystem and e is the accuracy of the navigation system.

In some examples, such as those shown in FIGS. 15-18, the interiormovement pattern may systematically cover the area located within theperimeter strip of the window surface; thus, the interior movementpattern may be determined substantially non-randomly.

More generally, it should be understood that features of the scanningpaths discussed above with reference to FIGS. 15-18 may be implementedin suitable interior movement patterns. For instance, the interiormovement pattern may be defined in the robot's programming (e.g. theprogramming of its processor(s)) such that the robot follows a scanningpath. Such a scanning path may, for instance, be such that it does notcross itself and/or be such that the robot cleans the area locatedwithin the perimeter strip of the window surface in a single continuousforwards movement.

More particularly, the scanning path may comprise a plurality ofparallel first segments, each of which preferably extends from aposition adjacent one edge of the window to a position adjacent theopposite edge of the window surface and may, for instance, extend acrosssubstantially the whole of the window surface.

As noted above, testing carried out by the Applicant indicates thatscanning paths where the parallel segments are oriented horizontally mayprovide a particularly good finish to the window surface. This isthought to be because residual cleaning fluid from previous parallelsegments, will tend, owing to gravity, to flow vertically downwards, andthus will be addressed in a generally continuous manner by subsequentparallel segments. In contrast, with vertically oriented parallelsegments, such residual cleaning fluid may be addressed in a morediscontinuous manner.

For similar reasons, it is considered that a scanning path that startsadjacent the top of the window and finishes adjacent the bottom of thewindow may provide a particularly good finish to the window surface.

Orientation-Based User Interface

The following section of the disclosure relates to the user interfacefor a window-cleaning robot.

As discussed further above, it is envisaged that the window-cleaningrobots described herein, such as the robot detailed above with referenceto FIG. 1 or the robot detailed above with reference to FIGS. 2 to 4,may operate in a number of operation modes. In each of these operationmodes, the various systems (for example the attachment, movement andcleaning systems) may be operated according to rules or policies thatthe robot has been programmed with (e.g. by suitable programming of itsprocessor(s)) and that are specific to that mode.

It is considered that, where a window cleaning robot that is programmed(e.g. by suitable programming of its processor(s)) to operate in anumber of operation modes has at least one orientation sensor (with therobot being configured to determine its orientation using suchorientation sensor(s)) it may be particularly intuitive if the robot isprogrammed (e.g. by suitable programming of its processor(s)) so as toallow the user to select one of the operation modes, with theuser-selected operation mode being determined at least in part by thedirection in which the robot is oriented.

In some examples, the robot's direction relative to the verticaldirection may be used to determine the user-selected operation mode. Inaddition, or instead, the robot's orientation may be defined within itsprogramming (e.g. in the programming of its processor(s)) such that itis parallel to its forwards direction (e.g. the forwards direction ofits movement system).

The robot may further include an operation mode control, actuation ofwhich determines, in part, the user-selected operation mode. The userinterface may be kept simple by this control having an unactuated and anactuated state, with the control being biased towards the unactuatedstate; for example, the operation mode control could be a push button,such as the play/pause button 710 of the robot shown in FIGS. 2 to 4.

As also discussed above, one of the operation modes for the robot may bea paused mode, where it remains stationary on the surface of the window(for example with the attachment system running in a low-power mode, inthe manner described above).

The robot may additionally be programmed (e.g. by suitable programmingof its processor(s)) with a number of “active” modes, in which the robotmoves, using the movement system, over the surface of the window. A widevariety of such “active” modes are contemplated. In one example, therobot may be programmed with a number of “cleaning” modes, in which thecleaning system is active as the robot moves over the surface of thewindow, so that the robot cleans the window surface; such “cleaning”modes may, for instance, differ in terms of the movement pattern thatthe robot follows when cleaning the window surface, and/or in terms ofthe portion of the window surface that is cleaned. In another example,the robot may be programmed with a “return to docking station” modewhere the robot window cleaner is configured to move to a dockingstation provided on the window surface.

The robot may be programmed (e.g. by suitable programming of itsprocessor(s)) such that each actuation of the operation mode controlswitches the robot between the paused mode and a user-selected one ofthe active modes, with the user-selected active mode being determinedbased on the robot direction. It will of course be appreciated thatfurther controls may be provided on the robot, such as, for example the“release” button described further above. As also discussed above withreference to FIG. 1, such controls may form a part of a user interface700 for a window cleaning robot 10.

In one specific example, in order to make the user interfaceparticularly simple, a single “play/pause” button may be provided, as isthe case with the robot of FIGS. 2 to 4. With the robot initially in the“paused” mode, it may hang on the surface of the window with theattachment system begin operate in a low-power mode, as described above.Then, when the “play/pause” button is pressed by the user, it will beginoperating in one of the active modes that is determined based on itsdirection. For instance, in the case that the robot direction isgenerally vertical a “full cleaning” mode may be selected, where therobot window cleaner is configured to clean substantially the entiresurface of the window, whereas in the case that the robot direction isgenerally horizontal a “spot cleaning” mode may be selected, where therobot window cleaner is configured to clean a predetermined area localto the robot.

In another arrangement, in the case that the robot direction ishorizontal and towards the left-hand side of the window surface, a “scandown” mode may be selected, where the robot is configured to clean thesurface of the window below the robot's current height, whereas in thecase where the robot direction is horizontal and towards the right-handside of the window surface robot, a “scan up” mode may be selected,where the robot is configured to clean the surface of the window abovethe robot's current height.

In a still further arrangement, the active modes defined in the robot'sprogramming (e.g. by suitable programming of its processor(s)) mayinclude two or more “scanning” modes, where in each “scanning” mode, therobot is programmed to clean a central portion of the window surface,which is substantially the entire window surface, with the exception ofa perimeter portion of the window surface adjacent the edge of thewindow. In such “scanning” modes, the robot may operate in a broadlysimilar manner to that described above with reference to FIGS. 15-19.Thus, it may, in each of these “scanning” modes, move along a pathdefined in the its programming such that the path comprises a pluralityof parallel segments. Each of these parallel path segments may extendparallel to a scanning direction corresponding to that “scanning” mode.Accordingly, the robot may be programmed (e.g. by suitable programmingof its processor(s)) to determine which of the scanning directions isclosest to its direction and to select the “scanning” mode correspondingto that closest scanning direction. For ease of use, only a vertical anda horizontal scanning mode may be provided, which may avoid the userhaving to orientate the robot with accuracy.

To further simplify the user interface, the attachment of the robot tothe surface may be carried out automatically, as soon as the robotapproaches the surface, in the manner described above.

This orientation based interface is very intuitive and simple to use andmay reduce the need for multiple buttons or displays/indications.

Movement System with Mechanically Linked Wheels

The following section of the disclosure relates to a movement system fora window-cleaning robot.

As may be seen from FIG. 2, the movement system of the robot 1 of FIGS.2 to 4 includes two sets of drive wheels 421A-422A, 421B-422B and twosupport members 450A, 450B, such as a sliding surface/point or castorwheels, which enable the robot to move smoothly over the window surface1000. As may also be seen from FIG. 2, the first and second sets ofdrive wheels 421A-422A, 421B-422B are spaced apart, one from the other,in width direction W, which is perpendicular to the forwards direction Fof the movement system. It may further be noted that the width directionW is parallel to the axes of the wheels. In addition, the wheels in eachset 421A-422A, 421B-422B are aligned perpendicular to this widthdirection W, i.e. in forwards direction F. Furthermore, the supportmembers 450A, 450B are spaced apart from the drive wheels in theforwards direction F.

The two sets of wheels 421A-422A, 421B-422B of the robot 1 may, forexample, be driven at different rates so as to move the robot along acurved path over the window surface, or to turn the robot on the spot.By contrast, driving the two sets of wheels 421A-422A, 421B-422B at thesame rate may move the robot 1 along a straight-line path over thewindow surface.

FIGS. 21A-21C are perspective views of one set of these pairs of wheels421, 422, together with the associated drive components, including themotor 410 for that pair of wheels 421, 422 and common drive gears 430.FIG. 21A shows a complete drive assembly 405 for one set of wheels; thehousing 440 for the wheels 421, 422 and the associated drive componentsare clearly visible in the drawing. By contrast, in FIG. 20B the housing440 is not shown, so as to more clearly illustrate the interior drivecomponents.

As is best shown in FIG. 21B, the pair of drive wheels 421, 422 ismechanically linked. Specifically, they are mechanically linked by meansof a number of common drive gears 430 that transfer rotation from themotor 410 for the pair of drive wheels 421, 422. Such a mechanicallylinked set of wheels 421, 422 may provide substantially greater tractionto the robot than a single wheel of the same size, while providing alower profile in a direction perpendicular to the window surface than alarger wheel that provides a similar traction force.

To increase the traction provided by the wheels, the wheels may beconfigured such that the attachment force provided by the attachmentsystem 600 causes each wheel 421, 422 to deform, thus increasing thecontact area between the window surface and the wheel 421, 422 inquestion. Hence, or otherwise, the radially exterior surfaces of thewheels 421, 422 may be made from a relatively softer material.

In the example shown in FIGS. 21A-21C, the wheels 421, 422 includetires, which may be made of a soft material, such as polyurethane, forexample 50 Shore polyurethane. When the robot is engaged with the windowsurface, with the attachment system active, the tires are somewhatflattened so that a still larger surface is created between the tire andthe window surface. This surface, doubled by the fact that two (or more)wheels 421, 422 are used, provides the required friction to assist therobot 1 in holding its own weight and driving against gravity.

In some cases, it may be beneficial for the wheels to have good tractionon a wet surface. The wheels 421, 422, or the tires thereof maytherefore contain grooves, which allow the water pressed between thetire and the window surface to drain and thus to reduce the wet layerbetween the tire and the window surface, hence providing good tractionon the window surface.

Such grooves on the exterior of wheel 422 are shown clearly in FIG. 21C,which is a perspective view of the wheels 421, 422 and the associatedwheel mount 441, which holds the wheels 421, 422 in position within therobot 1.

While in the specific example shown in FIGS. 2, and 21A-21C, each set ofdrive wheels 421A-422A, 421B-422B includes two wheels, it will beappreciated that any suitable number of drive wheels may be included ineach set. Similarly, any suitable number of support members may beprovided.

It will further be appreciated that the drive wheels might bemechanically linked in a variety of ways. Thus, rather than beingmechanically linked by common drive gears, the wheels could, forexample, be mechanically linked by a timing belt.

The robot of FIGS. 2 to 4, and 21A-21C is therefore viewed as being aspecific example of the much more general concept, whereby there isprovided a window-cleaning including a movement system, configured tomove the robot over a window surface and, thereby, to enable the robotto clean the window surface, the movement system comprising: a first anda second set of wheels configured to contact the window surface, each ofthe wheels being rotatable about a corresponding axis, the axes beingparallel to a first direction, the first set of wheels being spacedapart from the second set of wheels in the first direction; and at leastone motor for driving the wheels, the wheels thereby propelling therobot over the window surface; wherein the wheels within each of thefirst and the second sets are mechanically linked such that rotation ofany one wheel within a set causes movement of the other wheels withinthat set.

Certain products within the market make use of continuous or caterpillartracks to move over the window surface. It will be understood that suchproducts do not include wheels that are configured such that during usethey contact the window surface. Further, in comparison to suchproducts, a robot as defined immediately above (which comprises wheelsthat contact the window surface) may be lower cost (since it isgenerally simpler and may make greater use of standard components), mayavoid issues with variations in tension in such tracks (such variationmay be caused by changes in temperature, moisture etc.) and/or may leavefewer marks when turning. Nonetheless, a robot as defined above mayprovide similar traction forces to such products using caterpillartracks.

Combinations

It is envisaged that the concepts discussed above may be combined in avariety of ways within a window-cleaning robot.

For example, concepts disclosed in the “Navigation by a window-cleaningrobot” section may be implemented in a window-cleaning robot incombination with concepts disclosed in the “Orientation-based userinterface” section. Further, concepts disclosed in the“Orientation-based user interface” section may be implemented in awindow-cleaning robot in combination with concepts disclosed in the“Low-power attachment system” section. Furthermore, concepts disclosedin the “Orientation-based user interface” section may be implemented ina window-cleaning robot in combination with concepts disclosed in the“Automatic attachment to the window surface” section. Still further,concepts disclosed in the Cleaning system with a cleaning and apolishing pad” section may be implemented in a window-cleaning robot incombination with concepts disclosed in the “moveably-mounted cleaningpad” section. Of course, it will be appreciated that these are onlyexamples: still further combinations are envisaged.

Still further, as is noted a number of times in the disclosure above,although various concepts are described with reference to the robot ofFIG. 1 and the robot of FIGS. 2 to 4, such concepts do not rely on theparticular structure and configuration of these robots and may beimplemented more generally in window-cleaning robots.

More generally, it should be noted that the descriptions of the variousembodiments of the present invention have been presented for purposes ofillustration, but are not intended to be exhaustive or limited to theembodiments disclosed. Many modifications and variations will beapparent to those of ordinary skill in the art without departing fromthe scope and spirit of the described embodiments.

The terminology used herein was chosen to best explain the principles ofthe embodiments, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

The word “exemplary” is used herein to mean “serving as an example,instance or illustration”. Any embodiment described as “exemplary” isnot necessarily to be construed as preferred or advantageous over otherembodiments and/or to exclude the incorporation of features from otherembodiments.

The word “optionally” is used herein to mean “is provided in someembodiments and not provided in other embodiments”. Any particularembodiment of the invention may include a plurality of “optional”features unless such features conflict.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

1.-20. (canceled)
 21. A window-cleaning robot comprising: an attachmentsystem, for attaching the robot to the surface of a window, theattachment system comprising: an active-mode sealing member, attached tothe robot and configured to contact the surface of a window so as toseal a respective space between the robot and the window surface; one ormore paused-mode sealing members, each of which is attached to the robotand configured to contact the window surface so as to seal a respectivespace between the robot and the window surface; and one or more vacuumpumps, which are operable to reduce the air pressure within the spacessealed by the active-mode sealing member and the one or more paused-modesealing members; and a movement system, configured to move the robotover the window surface; the robot being programmed to operate in apaused mode, where the robot remains stationary on the surface of thewindow, and one or more active modes, where the robot moves over thesurface of window, using said movement system; the robot beingadditionally programmed such that, in each of said one or more activemodes, the vacuum pump(s) are caused to reduce the air pressure withinthe space sealed by the active-mode sealing member to a sufficientextent to attach the robot to the window surface, while permittingmovement of the robot over the window surface; the robot beingadditionally programmed such that, in said paused mode, the one or morevacuum pumps are caused to reduce the air pressure within the spacessealed by the paused-mode sealing member(s) to a sufficient extent toattach the robot to the window surface.
 22. The window-cleaning robot ofclaim 21, wherein said one or more vacuum pumps consume significantlyless power in said paused mode than in said active modes.
 23. Thewindow-cleaning robot of claim 21, further comprising one or more airpressure sensors, each air pressure sensor being arranged to sense theair pressure within the space between a corresponding one of the one ormore paused-mode sealing members and the window surface, wherein therobot is programmed such that the one or more vacuum pumps are operatedin dependence upon the air pressure within the respective spaces betweenthe one or more paused-mode sealing members and the window surface, asmeasured by the one or more air pressure sensors.
 24. Thewindow-cleaning robot of claim 23, wherein the robot is furtherprogrammed such that, during said paused mode, it causes the one or morevacuum pumps to reduce the air pressure within the respective spacessealed between the paused-mode sealing member(s) and the window surface,as measured by the air pressure sensor(s), to below a first thresholdvalue and, thereafter, it deactivates the one or more vacuum pumps untilthe air pressure within the space sealed by the one or more paused-modesealing members, as measured by the one or more air pressure sensor,rises above a second threshold value.
 25. The window-cleaning robot ofclaim 21, wherein each of the one or more paused-mode sealing members ismoveable between a first position, where it is spaced apart from thewindow surface, and a second position, where it contacts the windowsurface so as to seal said space between the robot and the windowsurface.
 26. The window-cleaning robot of claim 25, wherein each of theone or more paused-mode sealing members are biased towards said firstposition.
 27. The window-cleaning robot of claim 25, wherein movementbetween said first position and said position includes deformation ofthe one or more paused-mode sealing member.
 28. The window-cleaningrobot of claim 27, wherein said first position corresponds to asubstantially undeformed state of each paused-mode sealing member. 29.The window-cleaning robot of claim 25, wherein the robot is furtherprogrammed such that, during said paused mode, it causes each of the oneor more paused-mode sealing members to move to said second position and,during each of said active modes, it causes each of the one or morepaused-mode sealing members to return to said first position.
 30. Thewindow-cleaning robot of claim 25, wherein said active-mode sealingmember and said one or more paused-mode sealing members are arrangedsuch that said active-mode sealing member remains in contact with thewindow surface whether the robot is operating in said paused mode or inany of the active modes.
 31. The window-cleaning robot of claim 25,further comprising a respective internal space for each of said one ormore paused-mode sealing members, said one or more vacuum pumps beingconfigured to reduce the air pressure within said internal spaces so asto move each of said one or more paused-mode sealing members to saidsecond position.
 32. The window-cleaning robot of claim 31, furthercomprising, for each of said one or more paused-mode sealing members, arespective valve and a respective conduit, each conduit connecting theinternal space for the corresponding one of the paused-mode sealingmembers with the space sealed by that paused-mode sealing member via thecorresponding one of said valves; wherein each valve permits the passageof air through the corresponding one of the conduits when the pressurewithin the corresponding internal space is below a third threshold valueand inhibits the passage of air through the corresponding one of theconduits when the pressure within the corresponding internal space isabove said third threshold value.
 33. The window-cleaning robot of claim21, wherein said at least one vacuum pump includes first and second setsof vacuum pumps, said first set being dedicated to said active-modesealing member and said second set being dedicated to said one or morepaused-mode sealing members.
 34. The window-cleaning robot of claim 33,wherein each vacuum pump within said first set comprises one or moreimpellers.
 35. The window-cleaning robot of claim 33, wherein eachvacuum pump within said second set is a diaphragm vacuum pump.
 36. Thewindow-cleaning robot of claim 33, wherein said first set consists of asingle vacuum pump.
 37. The window-cleaning robot of claim 33, wherein adedicated vacuum pump is provided for each paused-mode sealing member.38. The window-cleaning robot of claim 33, wherein said second setconsists of a single vacuum pump.
 39. The window-cleaning robot of claim21, wherein said one or more paused-mode sealing members are locatedwithin said active-mode sealing member.